{"title":"Gratings \u0026 Slits","description":null,"products":[{"product_id":"shelyak-se0005","title":"Shelyak Grating module for the Lhires III - 2400 l\/mm","description":"\u003cul class=\"DAV-feature-list\"\u003e\n\u003cli\u003eGrating Ruling: 2400 lines\/mm\u003c\/li\u003e\n\u003cli\u003eInstrument Compatibility: Shelyak Lhires III Spectroscope\u003c\/li\u003e\n\u003cli\u003ePrimary Application: High-Resolution Spectroscopy\u003c\/li\u003e\n\u003cli\u003eFunction: Direct replacement for the standard Lhires III grating\u003c\/li\u003e\n\u003c\/ul\u003e\n\u003c!-- more --\u003e\n\u003cul class=\"tabs\"\u003e\n\u003cli class=\"active\"\u003eDescription\u003c\/li\u003e\n\u003cli\u003eFAQ\u003c\/li\u003e\n\n\u003cli\u003eDownloads\u003c\/li\u003e\n\u003cli\u003eWarranty\u003c\/li\u003e\n\u003c\/ul\u003e\n\u003cul class=\"tabs-content\"\u003e\n\u003cli class=\"active\"\u003e\n\u003cdiv\u003e\n\u003cdiv class=\"DAV-bg-light\"\u003e\n\u003cdiv class=\"DAV-section-center\"\u003e\n\u003ch2\u003eGrating module for the Lhires III - 2400 l\/mm\u003c\/h2\u003e\n\u003cp\u003eThis is the standard, high-resolution grating module for the Shelyak Lhires III spectroscope, featuring a 2400 lines\/mm ruling. The Lhires III instrument is supplied from the factory with this 2400 l\/mm grating to deliver its maximum native resolving power.\u003c\/p\u003e\n\u003c\/div\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-bg-light\"\u003e\n\u003cdiv class=\"DAV-section\"\u003e\n\u003ch3\u003eThe Standard 2400 l\/mm High-Resolution Grating for Lhires III\u003c\/h3\u003e\n\u003cp\u003eEngineered as the default optical component for the Lhires III, this 2400 lines\/mm grating module is the key to achieving the instrument's highest spectral resolution. It is designed for detailed analysis of stellar atmospheres, Be star emission lines, and other targets requiring fine spectral detail.\u003c\/p\u003e\n\u003cp\u003eThis module serves as a direct replacement for the original grating included with your Lhires III. While other complementary gratings are available to change the instrument's resolution for different applications, the 2400 l\/mm version remains the primary choice for high-resolution work.\u003c\/p\u003e\n\u003c\/div\u003e\n\u003c\/div\u003e\n\u003c\/div\u003e\n\u003c\/li\u003e\n\u003cli\u003e\n\u003cdiv class=\"DAV-accordion\"\u003e\n\u003ch3 class=\"DAV-accordion-Q\"\u003eWhat is the primary purpose of the 2400 l\/mm grating for the Lhires III?\u003c\/h3\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion-A\"\u003e\n\u003cp\u003eThe \u003cstrong\u003e2400 lines\/mm grating\u003c\/strong\u003e is designed to provide the highest possible spectral resolution for the Lhires III spectroscope. It is intended for scientific applications where resolving fine details in a star's spectrum is critical, such as measuring doppler shifts or analyzing narrow emission and absorption lines.\u003c\/p\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion\"\u003e\n\u003ch3 class=\"DAV-accordion-Q\"\u003eIs this 2400 l\/mm grating an upgrade for the Lhires III?\u003c\/h3\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion-A\"\u003e\n\u003cp\u003eNo, this is not an upgrade. The Shelyak Lhires III spectroscope is sold with the \u003cstrong\u003e2400 l\/mm grating module\u003c\/strong\u003e as its standard component. This product is a direct, factory-spec replacement for a lost or damaged original grating.\u003c\/p\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion\"\u003e\n\u003ch3 class=\"DAV-accordion-Q\"\u003eWhy would I need to replace the 2400 l\/mm grating on my Lhires III?\u003c\/h3\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion-A\"\u003e\n\u003cp\u003eYou would typically purchase this module only if the original grating that came with your Lhires III was damaged, degraded, or lost. Since it is the standard grating, this module ensures your instrument is restored to its original high-resolution capabilities.\u003c\/p\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion\"\u003e\n\u003ch3 class=\"DAV-accordion-Q\"\u003eHow does the 2400 l\/mm grating perform on a Be star like Gamma Cassiopeiae?\u003c\/h3\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion-A\"\u003e\n\u003cp\u003eThe high resolution of the \u003cstrong\u003e2400 l\/mm grating\u003c\/strong\u003e is ideal for studying Be stars like Gamma Cassiopeiae (γ Cas). It allows you to clearly resolve the double-peaked profile of the Hydrogen-alpha (Hα) emission line, which originates from the star's circumstellar disk. This level of detail is essential for monitoring V\/R (violet-to-red peak) variations and changes in the disk structure.\u003c\/p\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion\"\u003e\n\u003ch3 class=\"DAV-accordion-Q\"\u003eWhen should I use a lower-resolution grating instead of this 2400 l\/mm module for my Lhires III?\u003c\/h3\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion-A\"\u003e\n\u003cp\u003eWhile the \u003cstrong\u003e2400 l\/mm grating\u003c\/strong\u003e provides maximum detail, it covers a very small spectral range. You should switch to a lower-resolution grating (e.g., 600 or 1200 l\/mm) when you need to:\n\u003c\/p\u003e\n\u003cul\u003e\n\u003cli\u003e\n\u003cstrong\u003eCapture a wider wavelength range\u003c\/strong\u003e in a single exposure, such as when classifying star types.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eStudy faint objects\u003c\/strong\u003e like quasars or supernovae, where collecting more light over a broader band is more important than high resolution.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003ePerform initial surveys\u003c\/strong\u003e of targets before focusing on a specific spectral line with the high-resolution grating.\u003c\/li\u003e\n\u003c\/ul\u003e\n\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion\"\u003e\n\u003ch3 class=\"DAV-accordion-Q\"\u003eIs it difficult to install the 2400 l\/mm grating module in the Lhires III?\u003c\/h3\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion-A\"\u003e\n\u003cp\u003eNo, the grating modules for the Lhires III are designed to be user-interchangeable. The process involves opening the instrument cover and carefully swapping the modules. Refer to the official Lhires III user manual for detailed, step-by-step instructions to ensure proper handling and alignment.\u003c\/p\u003e\n\u003c\/div\u003e\n\u003c\/li\u003e\n\n\u003cli\u003e\n\u003cul class=\"DAV-grid\"\u003e\n\u003cli class=\"DAV-grid-item\"\u003e\u003ca href=\"https:\/\/cdn.shopify.com\/s\/files\/1\/0753\/5280\/1565\/files\/Shelyak_Lhires_III_Manual.pdf\" target=\"_blank\"\u003e\u003csvg class=\"DAV-img-box\" viewbox=\"0 0 512 512\" xmlns=\"http:\/\/www.w3.org\/2000\/svg\"\u003e\u003cpath d=\"M0 64C0 28.7 28.7 0 64 0L224 0l0 128c0 17.7 14.3 32 32 32l128 0 0 144-208 0c-35.3 0-64 28.7-64 64l0 144-48 0c-35.3 0-64-28.7-64-64L0 64zm384 64l-128 0L256 0 384 128zM176 352l32 0c30.9 0 56 25.1 56 56s-25.1 56-56 56l-16 0 0 32c0 8.8-7.2 16-16 16s-16-7.2-16-16l0-48 0-80c0-8.8 7.2-16 16-16zm32 80c13.3 0 24-10.7 24-24s-10.7-24-24-24l-16 0 0 48 16 0zm96-80l32 0c26.5 0 48 21.5 48 48l0 64c0 26.5-21.5 48-48 48l-32 0c-8.8 0-16-7.2-16-16l0-128c0-8.8 7.2-16 16-16zm32 128c8.8 0 16-7.2 16-16l0-64c0-8.8-7.2-16-16-16l-16 0 0 96 16 0zm80-112c0-8.8 7.2-16 16-16l48 0c8.8 0 16 7.2 16 16s-7.2 16-16 16l-32 0 0 32 32 0c8.8 0 16 7.2 16 16s-7.2 16-16 16l-32 0 0 48c0 8.8-7.2 16-16 16s-16-7.2-16-16l0-64 0-64z\" fill=\"#0047a7\"\u003e\u003c\/path\u003e\u003c\/svg\u003e\n\u003cdiv\u003e\n\u003cp class=\"DAV-item-title\"\u003eShelyak Lhires III Manual\u003c\/p\u003e\n\u003c\/div\u003e\n\u003c\/a\u003e\u003c\/li\u003e\n\u003c\/ul\u003e\n\u003c\/li\u003e\n\u003cli\u003e\n\u003ca href=\"https:\/\/davidastro.com\/pages\/shelyak-warranty-policy\" rel=\"noopener\" target=\"_blank\"\u003eShelyak 1-Year Warranty\u003c\/a\u003e\n\u003c\/li\u003e\n\u003c\/ul\u003e","brand":"Shelyak","offers":[{"title":"Default Title","offer_id":52943042412829,"sku":"SHK-SE0005","price":1035.0,"currency_code":"CAD","in_stock":true}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0753\/5280\/1565\/files\/Shelyak-Grating-module-for-the-Lhires-III-2400-l-mm-1_90238cf8-88d4-4d27-85e3-f830bc715a3d.jpg?v=1789616196"},{"product_id":"shelyak-se0006","title":"Shelyak Grating module for the Lhires III - 1200 l\/mm","description":"\u003cul class=\"DAV-feature-list\"\u003e\n\u003cli\u003e1200 lines\/mm Grating\u003c\/li\u003e\n\u003cli\u003eDirect-Fit Module for Lhires III\u003c\/li\u003e\n\u003cli\u003eExpands Spectrograph Wavelength Coverage\u003c\/li\u003e\n\u003cli\u003eIdeal for Spectroscopic Surveys\u003c\/li\u003e\n\u003cli\u003eInterchangeable with Standard Grating\u003c\/li\u003e\n\u003c\/ul\u003e\n\u003c!-- more --\u003e\n\u003cul class=\"tabs\"\u003e\n\u003cli class=\"active\"\u003eDescription\u003c\/li\u003e\n\u003cli\u003eFAQ\u003c\/li\u003e\n\u003cli\u003eSpecifications\u003c\/li\u003e\n\u003cli\u003eIn the Box\u003c\/li\u003e\n\u003cli\u003eWarranty\u003c\/li\u003e\n\u003c\/ul\u003e\n\u003cul class=\"tabs-content\"\u003e\n\u003cli class=\"active\"\u003e\n\u003cdiv\u003e\n\u003cdiv class=\"DAV-bg-light\"\u003e\n\u003cdiv class=\"DAV-section-center\"\u003e\n\u003ch2\u003eGrating module for the Lhires III - 1200 l\/mm\u003c\/h2\u003e\n\u003cp\u003eSwap the standard 2400 l\/mm grating in your Shelyak Lhires III spectrograph for this 1200 lines\/mm module to trade high resolution for significantly broader spectral coverage in a single exposure. This module is an essential accessory for observers who need to characterize objects with unknown features or monitor phenomena across a wide spectral range, such as supernovae or comets.\u003c\/p\u003e\n\u003c\/div\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-bg-light\"\u003e\n\u003cdiv class=\"DAV-section\"\u003e\n\u003ch3\u003eThe 1200 l\/mm Trade-Off: Broader Wavelength Coverage at Lower Resolution\u003c\/h3\u003e\n\u003cp\u003eIn spectroscopy, a grating's line density dictates the trade-off between spectral resolution and wavelength coverage. A higher line count, like the Lhires III's standard 2400 l\/mm grating, spreads the light out more, delivering higher resolution over a smaller spectral window. This 1200 l\/mm grating does the opposite; with fewer lines, it produces a less dispersed spectrum, allowing a much wider range of wavelengths to fall onto your sensor in a single frame.\u003c\/p\u003e\n\u003cp\u003eThis capability is critical for survey work, initial classification of variable stars, or capturing the full profile of objects with broad emission lines. Instead of taking multiple exposures to piece together a spectrum, you can capture the entire visible range at once, saving valuable observing time.\u003c\/p\u003e\n\u003c\/div\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-bg-light\"\u003e\n\u003cdiv class=\"DAV-section\"\u003e\n\u003ch3\u003e1200 l\/mm vs. 2400 l\/mm: Choosing the Right Grating for Your Target\u003c\/h3\u003e\n\u003cp\u003eThe standard 2400 l\/mm grating is the correct tool for the high-resolution work the Lhires III is famous for—measuring precise radial velocities, studying detailed line profiles of Be stars, or resolving close binary systems spectroscopically. It prioritizes detail over breadth.\u003c\/p\u003e\n\u003cp\u003eThe 1200 l\/mm grating module excels when the scientific goal is characterization rather than fine measurement. It is the superior choice for:\u003c\/p\u003e\n\u003cul\u003e\n\u003cli\u003e\n\u003cstrong\u003eSupernova and Nova Spectroscopy:\u003c\/strong\u003e Capturing the evolution of multiple, broad spectral features (like Silicon II or Hydrogen lines) simultaneously as the object brightens and fades.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eQuasar and AGN Characterization:\u003c\/strong\u003e Identifying highly redshifted emission lines across a wide spectral range to determine the object's distance and nature.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eCometary Analysis:\u003c\/strong\u003e Observing molecular emission bands from species like C2 (Swan bands) which span a significant portion of the visible spectrum.\u003c\/li\u003e\n\u003c\/ul\u003e\n\u003c\/div\u003e\n\u003c\/div\u003e\n\u003c\/div\u003e\n\u003c\/li\u003e\n\u003cli\u003e\n\u003cdiv class=\"DAV-accordion\"\u003e\n\u003ch3 class=\"DAV-accordion-Q\"\u003eWhy would I choose the 1200 l\/mm grating for my Lhires III over the standard 2400 l\/mm?\u003c\/h3\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion-A\"\u003e\n\u003cp\u003eYou would choose the \u003cstrong\u003e1200 l\/mm grating\u003c\/strong\u003e when your primary goal is to capture the widest possible range of wavelengths in a single exposure. The standard \u003cstrong\u003e2400 l\/mm grating\u003c\/strong\u003e provides higher resolution but covers a much narrower spectral window. The 1200 l\/mm module is for survey work and broad characterization, not fine detail analysis.\u003c\/p\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion\"\u003e\n\u003ch3 class=\"DAV-accordion-Q\"\u003eWhat is the main advantage of a lower-resolution grating like this 1200 l\/mm module for the Lhires III?\u003c\/h3\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion-A\"\u003e\n\u003cp\u003eThe main advantage is \u003cstrong\u003eefficiency\u003c\/strong\u003e. For objects like supernovae, comets, or quasars, important spectral features can be spread far apart. The 1200 l\/mm grating allows you to capture all of them in one shot, saving time and simplifying data acquisition compared to creating a mosaic of multiple high-resolution exposures.\u003c\/p\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion\"\u003e\n\u003ch3 class=\"DAV-accordion-Q\"\u003eIs the 1200 l\/mm grating module difficult to install in the Lhires III?\u003c\/h3\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion-A\"\u003e\n\u003cp\u003eNo, the Lhires III is designed for interchangeable grating modules. The process involves opening the access panel and carefully swapping the existing module with the new one. Always refer to your Lhires III manual for the specific procedure to avoid damaging the delicate grating surface.\u003c\/p\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion\"\u003e\n\u003ch3 class=\"DAV-accordion-Q\"\u003eIf I want to study the H-alpha line profile of Vega (Alpha Lyrae) with my Lhires III, is the 1200 l\/mm grating the right choice?\u003c\/h3\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion-A\"\u003e\n\u003cp\u003eNo. For detailed analysis of a single, narrow spectral line like H-alpha, the standard \u003cstrong\u003e2400 l\/mm grating is the correct tool\u003c\/strong\u003e. Its higher resolution is necessary to reveal subtle shifts and profile changes. The 1200 l\/mm grating would show the line, but without the detail needed for scientific measurement of its profile.\u003c\/p\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion\"\u003e\n\u003ch3 class=\"DAV-accordion-Q\"\u003eI'm using my Lhires III on an 8\" SCT to monitor a supernova. Why is the 1200 l\/mm grating module a good tool for this?\u003c\/h3\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion-A\"\u003e\n\u003cp\u003eSupernovae exhibit broad, evolving spectral features across the entire visible spectrum. The \u003cstrong\u003e1200 l\/mm grating's\u003c\/strong\u003e wide spectral coverage is ideal for this task, as it allows you to capture the appearance and evolution of key features like the Silicon II (Si II) absorption line in Type Ia supernovae and the broad Hydrogen lines in Type II, all within a single frame.\u003c\/p\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion\"\u003e\n\u003ch3 class=\"DAV-accordion-Q\"\u003eDoes using the 1200 l\/mm grating module change the calibration process for the Lhires III?\u003c\/h3\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion-A\"\u003e\n\u003cp\u003eYes, absolutely. You must perform a new spectral calibration after installing the 1200 l\/mm grating. The dispersion (angstroms per pixel) is different from the 2400 l\/mm grating, so your previous calibration files will no longer be accurate. You will need to create and save a new calibration profile for this specific setup.\u003c\/p\u003e\n\u003c\/div\u003e\n\u003c\/li\u003e\n\u003cli\u003e\n\u003ctable class=\"DAV-specifications\"\u003e\n\u003ctbody\u003e\n\u003ctr\u003e\n\u003ctd\u003eGrating Density\u003c\/td\u003e\n\u003ctd\u003e1200 lines\/mm\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eCompatibility\u003c\/td\u003e\n\u003ctd\u003eShelyak Lhires III Spectrograph\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eApplication\u003c\/td\u003e\n\u003ctd\u003eLow Resolution, Wide Field Spectroscopy\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003c\/tbody\u003e\n\u003c\/table\u003e\n\u003c\/li\u003e\n\u003cli\u003e\n\u003cul class=\"DAV-grid\"\u003e\n\u003cli class=\"DAV-grid-item\"\u003e\n\u003cdiv\u003e\n\u003cp class=\"DAV-item-title\"\u003e1200 l\/mm Grating Module for Lhires III\u003c\/p\u003e\n\u003cp class=\"DAV-item-subtitle\"\u003e× 1\u003c\/p\u003e\n\u003c\/div\u003e\n\u003c\/li\u003e\n\u003c\/ul\u003e\n\u003c\/li\u003e\n\n\u003cli\u003e\n\u003ca href=\"https:\/\/davidastro.com\/pages\/shelyak-warranty-policy\" rel=\"noopener\" target=\"_blank\"\u003eShelyak 1-Year Warranty\u003c\/a\u003e\n\u003c\/li\u003e\n\u003c\/ul\u003e","brand":"Shelyak","offers":[{"title":"Default Title","offer_id":52943042740509,"sku":"SHK-SE0006","price":1018.0,"currency_code":"CAD","in_stock":true}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0753\/5280\/1565\/files\/Shelyak-Grating-module-for-the-Lhires-III-2400-l-mm-1_b61d3287-6af2-4150-ae9e-8b534d66107a.jpg?v=1789616204"},{"product_id":"shelyak-se0007","title":"Shelyak Grating module for the Lhires III - 600 l\/mm","description":"\u003cul class=\"DAV-feature-list\"\u003e\n\u003cli\u003e\n\u003cstrong\u003eGrating Density:\u003c\/strong\u003e 600 lines\/mm\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eInstrument Compatibility:\u003c\/strong\u003e Shelyak Lhires III Spectroscope\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003ePrimary Application:\u003c\/strong\u003e Low-resolution, wide-band spectroscopy\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eFunction:\u003c\/strong\u003e Expands the Lhires III's capabilities for observing faint, broad-emission objects\u003c\/li\u003e\n\u003c\/ul\u003e\n\u003c!-- more --\u003e\n\u003cul class=\"tabs\"\u003e\n\u003cli class=\"active\"\u003eDescription\u003c\/li\u003e\n\u003cli\u003eFAQ\u003c\/li\u003e\n\u003cli\u003eSpecifications\u003c\/li\u003e\n\u003cli\u003eIn the Box\u003c\/li\u003e\n\u003cli\u003eDownloads\u003c\/li\u003e\n\u003cli\u003eWarranty\u003c\/li\u003e\n\u003c\/ul\u003e\n\u003cul class=\"tabs-content\"\u003e\n\u003cli class=\"active\"\u003e\n\u003cdiv\u003e\n\u003cdiv class=\"DAV-bg-light\"\u003e\n\u003cdiv class=\"DAV-section-center\"\u003e\n\u003ch2\u003eGrating module for the Lhires III - 600 l\/mm\u003c\/h2\u003e\n\u003cp\u003eThis 600 lines\/mm grating module fundamentally alters the capabilities of your Lhires III spectroscope, trading the high resolution of the standard 2400 l\/mm grating for significantly broader wavelength coverage in a single exposure. It transforms the Lhires III from a specialized high-resolution instrument into a more versatile tool for surveying a wider range of celestial targets.\u003c\/p\u003e\n\u003c\/div\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-bg-light\"\u003e\n\u003cdiv class=\"DAV-section\"\u003e\n\u003ch3\u003eThe Core Trade-Off: Swapping Resolution for Broad Spectral Range\u003c\/h3\u003e\n\u003cp\u003eIn spectroscopy, resolution and spectral range are inversely related. The standard 2400 l\/mm grating disperses light widely to resolve fine details, but can only capture a narrow slice of the spectrum. This 600 l\/mm grating module does the opposite, concentrating the spectrum to fit a much wider range of wavelengths onto your sensor at the expense of resolving power.\u003c\/p\u003e\n\u003cp\u003eThis lower dispersion makes the 600 l\/mm grating ideal for initial characterization of unknown objects or for studying phenomena that span the entire visible spectrum. It also increases throughput, delivering a brighter spectrum that is critical for faint targets.\u003c\/p\u003e\n\u003c\/div\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-bg-light\"\u003e\n\u003cdiv class=\"DAV-section\"\u003e\n\u003ch3\u003eNew Targets for Your Lhires III: From Novae to Comets\u003c\/h3\u003e\n\u003cp\u003eBy prioritizing spectral range over detail, this module opens up new observational possibilities for the Lhires III. It allows you to effectively study objects with broad emission or absorption features that are difficult to analyze with a high-resolution grating.\u003c\/p\u003e\n\u003cul\u003e\n\u003cli\u003e\n\u003cstrong\u003eTransient Events:\u003c\/strong\u003e Capture the entire visible spectrum of a supernova or nova in a single shot to classify its type and evolution.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eComets:\u003c\/strong\u003e Analyze the broad emission bands from molecules like C2 (Swan bands) in a comet's coma.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eEmission Nebulae:\u003c\/strong\u003e Measure the relative intensities of key emission lines (like H-alpha, H-beta, and OIII) across a wide spectral range simultaneously.\u003c\/li\u003e\n\u003c\/ul\u003e\n\u003c\/div\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-bg-light\"\u003e\n\u003cdiv class=\"DAV-section\"\u003e\n\u003ch3\u003e600 l\/mm vs. the Standard 2400 l\/mm Grating\u003c\/h3\u003e\n\u003cp\u003eChoosing the right grating depends entirely on your scientific goal. This 600 l\/mm module complements the stock grating, giving your Lhires III dual-mode capability.\u003c\/p\u003e\n\u003cul\u003e\n\u003cli\u003e\n\u003cstrong\u003e600 l\/mm Grating (This Module):\u003c\/strong\u003e Best for low-resolution survey work, spectral classification, and observing faint, extended objects. It captures a wide spectral range, ideal for understanding the overall nature of a target.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003e2400 l\/mm Grating (Standard):\u003c\/strong\u003e Best for high-resolution studies of specific, narrow spectral lines. It is the tool for measuring precise Doppler shifts to determine stellar radial velocities or for analyzing the detailed profiles of absorption lines in bright stars.\u003c\/li\u003e\n\u003c\/ul\u003e\n\u003c\/div\u003e\n\u003c\/div\u003e\n\u003c\/div\u003e\n\u003c\/li\u003e\n\u003cli\u003e\n\u003cdiv class=\"DAV-accordion\"\u003e\n\u003ch3 class=\"DAV-accordion-Q\"\u003eWhat is the main reason to use the 600 l\/mm grating in my Lhires III?\u003c\/h3\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion-A\"\u003e\n\u003cp\u003eThe primary reason is to capture a much \u003cstrong\u003ewider range of wavelengths\u003c\/strong\u003e in a single image. While the standard 2400 l\/mm grating provides very high resolution for studying fine details, this 600 l\/mm grating is designed for survey work, classifying objects like supernovae, or studying targets with broad emission features like comets.\u003c\/p\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion\"\u003e\n\u003ch3 class=\"DAV-accordion-Q\"\u003eHow will the 600 l\/mm grating change my Lhires III's view of a bright star like Vega (Alpha Lyrae)?\u003c\/h3\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion-A\"\u003e\n\u003cp\u003eWith the standard 2400 l\/mm grating, you might focus on the detailed shape of a single hydrogen line (like H-alpha) in Vega's spectrum. With the 600 l\/mm grating, you would see the entire Balmer series of hydrogen lines across the visible spectrum at once, along with Vega's overall spectral curve, but with much less detail in each individual line.\u003c\/p\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion\"\u003e\n\u003ch3 class=\"DAV-accordion-Q\"\u003eCan I use the 600 l\/mm grating to study the spectrum of a comet?\u003c\/h3\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion-A\"\u003e\n\u003cp\u003eYes, this is an ideal application. Comets often show broad emission bands from various molecules. The 600 l\/mm grating allows you to capture these features across a wide spectral range, which is perfect for identifying the comet's chemical composition.\u003c\/p\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion\"\u003e\n\u003ch3 class=\"DAV-accordion-Q\"\u003eIs the 600 l\/mm grating module difficult to install in the Lhires III?\u003c\/h3\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion-A\"\u003e\n\u003cp\u003eNo, the Lhires III was designed for interchangeable grating modules. The process is straightforward, allowing you to swap between high and low-resolution modes depending on your observing target for the night. Refer to the Lhires III manual for detailed instructions.\u003c\/p\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion\"\u003e\n\u003ch3 class=\"DAV-accordion-Q\"\u003eWill this 600 l\/mm grating work with other spectroscopes besides the Lhires III?\u003c\/h3\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion-A\"\u003e\n\u003cp\u003eThis module is specifically designed and mounted for the Shelyak Lhires III spectroscope. It is not intended for use in other instruments due to its specific mechanical interface.\u003c\/p\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion\"\u003e\n\u003ch3 class=\"DAV-accordion-Q\"\u003eDoes lower resolution mean lower quality data with the 600 l\/mm grating?\u003c\/h3\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion-A\"\u003e\n\u003cp\u003eNot at all. \"Resolution\" refers to the ability to separate closely spaced spectral lines. Lower resolution is a deliberate choice to achieve a different scientific goal—namely, wider spectral coverage. For tasks like classifying a supernova or measuring the overall color of an asteroid, the data from the 600 l\/mm grating is not only high quality but is the more appropriate choice.\u003c\/p\u003e\n\u003c\/div\u003e\n\u003c\/li\u003e\n\u003cli\u003e\n\u003ctable class=\"DAV-specifications\"\u003e\n\u003ctbody\u003e\n\u003ctr\u003e\n\u003ctd\u003eGrating Density\u003c\/td\u003e\n\u003ctd\u003e600 lines\/mm\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eIntended Instrument\u003c\/td\u003e\n\u003ctd\u003eShelyak Lhires III Spectroscope\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eResolution Class\u003c\/td\u003e\n\u003ctd\u003eLow Resolution\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eSpectral Coverage\u003c\/td\u003e\n\u003ctd\u003eWide Band\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003c\/tbody\u003e\n\u003c\/table\u003e\n\u003c\/li\u003e\n\u003cli\u003e\n\u003cul class=\"DAV-grid\"\u003e\n\u003cli class=\"DAV-grid-item\"\u003e\n\u003cdiv\u003e\n\u003cp class=\"DAV-item-title\"\u003e600 l\/mm Grating Module for Lhires III\u003c\/p\u003e\n\u003cp class=\"DAV-item-subtitle\"\u003e× 1\u003c\/p\u003e\n\u003c\/div\u003e\n\u003c\/li\u003e\n\u003c\/ul\u003e\n\u003c\/li\u003e\n\u003cli\u003e\n\u003cul class=\"DAV-grid\"\u003e\n\u003cli class=\"DAV-grid-item\"\u003e\u003ca href=\"https:\/\/cdn.shopify.com\/s\/files\/1\/0753\/5280\/1565\/files\/Shelyak_Lhires_III_Manual.pdf\" target=\"_blank\"\u003e\u003csvg class=\"DAV-img-box\" viewbox=\"0 0 512 512\" xmlns=\"http:\/\/www.w3.org\/2000\/svg\"\u003e\u003cpath d=\"M0 64C0 28.7 28.7 0 64 0L224 0l0 128c0 17.7 14.3 32 32 32l128 0 0 144-208 0c-35.3 0-64 28.7-64 64l0 144-48 0c-35.3 0-64-28.7-64-64L0 64zm384 64l-128 0L256 0 384 128zM176 352l32 0c30.9 0 56 25.1 56 56s-25.1 56-56 56l-16 0 0 32c0 8.8-7.2 16-16 16s-16-7.2-16-16l0-48 0-80c0-8.8 7.2-16 16-16zm32 80c13.3 0 24-10.7 24-24s-10.7-24-24-24l-16 0 0 48 16 0zm96-80l32 0c26.5 0 48 21.5 48 48l0 64c0 26.5-21.5 48-48 48l-32 0c-8.8 0-16-7.2-16-16l0-128c0-8.8 7.2-16 16-16zm32 128c8.8 0 16-7.2 16-16l0-64c0-8.8-7.2-16-16-16l-16 0 0 96 16 0zm80-112c0-8.8 7.2-16 16-16l48 0c8.8 0 16 7.2 16 16s-7.2 16-16 16l-32 0 0 32 32 0c8.8 0 16 7.2 16 16s-7.2 16-16 16l-32 0 0 48c0 8.8-7.2 16-16 16s-16-7.2-16-16l0-64 0-64z\" fill=\"#0047a7\"\u003e\u003c\/path\u003e\u003c\/svg\u003e\n\u003cdiv\u003e\n\u003cp class=\"DAV-item-title\"\u003eShelyak Lhires III Manual\u003c\/p\u003e\n\u003c\/div\u003e\n\u003c\/a\u003e\u003c\/li\u003e\n\u003c\/ul\u003e\n\u003c\/li\u003e\n\u003cli\u003e\n\u003ca href=\"https:\/\/davidastro.com\/pages\/shelyak-warranty-policy\" rel=\"noopener\" target=\"_blank\"\u003eShelyak 1-Year Warranty\u003c\/a\u003e\n\u003c\/li\u003e\n\u003c\/ul\u003e","brand":"Shelyak","offers":[{"title":"Default Title","offer_id":52943043068189,"sku":"SHK-SE0007","price":1018.0,"currency_code":"CAD","in_stock":true}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0753\/5280\/1565\/files\/Shelyak-Grating-module-for-the-Lhires-III-2400-l-mm-1_6e2fbb50-e60f-4907-985d-753b59101eb6.jpg?v=1789616212"},{"product_id":"shelyak-se0008","title":"Shelyak Grating module for the Lhires III - 300 l\/mm","description":"\u003cul class=\"DAV-feature-list\"\u003e\n\u003cli\u003eGrating for Lhires III Spectroscope\u003c\/li\u003e\n\u003cli\u003e300 lines\/mm Ruling\u003c\/li\u003e\n\u003cli\u003eProvides Lower Resolution and Wider Spectral Range\u003c\/li\u003e\n\u003cli\u003eComplements the Standard 2400 l\/mm Grating\u003c\/li\u003e\n\u003c\/ul\u003e\n\u003c!-- more --\u003e\n\u003cul class=\"tabs\"\u003e\n\u003cli class=\"active\"\u003eDescription\u003c\/li\u003e\n\u003cli\u003eFAQ\u003c\/li\u003e\n\u003cli\u003eSpecifications\u003c\/li\u003e\n\u003cli\u003eIn the Box\u003c\/li\u003e\n\u003cli\u003eDownloads\u003c\/li\u003e\n\u003cli\u003eWarranty\u003c\/li\u003e\n\u003c\/ul\u003e\n\u003cul class=\"tabs-content\"\u003e\n\u003cli class=\"active\"\u003e\n\u003cdiv\u003e\n\u003cdiv class=\"DAV-bg-light\"\u003e\n\u003cdiv class=\"DAV-section-center\"\u003e\n\u003ch2\u003eGrating module for the Lhires III - 300 l\/mm\u003c\/h2\u003e\n\u003cp\u003eThe Shelyak Grating module for the Lhires III - 300 l\/mm is an optional component designed to trade the high resolution of the standard 2400 l\/mm grating for significantly broader spectral coverage in a single exposure. This 300 lines\/mm grating fundamentally alters the instrument's capabilities, making it suitable for analyzing entire spectral classes of stars or faint, extended objects where capturing the full spectrum is more critical than resolving fine absorption lines.\u003c\/p\u003e\n\u003c\/div\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-bg-light\"\u003e\n\u003cdiv class=\"DAV-section\"\u003e\n\u003ch3\u003eFrom 2400 l\/mm to 300 l\/mm: Expanding Your Lhires III's Capabilities\u003c\/h3\u003e\n\u003cp\u003eThe Shelyak Lhires III spectroscope is supplied with a 2400 lines\/mm grating, engineered specifically for high-resolution studies of specific spectral features. This 300 l\/mm grating module offers the inverse capability, transforming your specialized instrument into a versatile survey tool.\u003c\/p\u003e\n\u003cp\u003eBy reducing the line count, the 300 l\/mm grating disperses light over a smaller angle, allowing a much wider range of wavelengths to fall onto your sensor at once. This trade-off is the core purpose of the module: sacrificing resolving power to gain spectral breadth.\u003c\/p\u003e\n\u003cul\u003e\n\u003cli\u003e\n\u003cstrong\u003eStandard 2400 l\/mm Grating:\u003c\/strong\u003e Delivers high resolution over a narrow spectral window. It is ideal for measuring the Doppler shift in a binary star's H-alpha line or studying the fine structure of a planetary nebula.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eOptional 300 l\/mm Grating:\u003c\/strong\u003e Provides lower resolution across a very wide spectral window. It is built for capturing the overall spectral energy distribution of an object, classifying a star's type, or monitoring a supernova's evolution across its entire visible spectrum.\u003c\/li\u003e\n\u003c\/ul\u003e\n\u003c\/div\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-bg-light\"\u003e\n\u003cdiv class=\"DAV-section\"\u003e\n\u003ch3\u003eApplications for Low-Resolution Spectroscopy with the 300 l\/mm Grating\u003c\/h3\u003e\n\u003cp\u003eWith this module, your Lhires III becomes an ideal instrument for spectrophotometry and the study of faint targets. Capturing the spectrum of a dim comet, a distant quasar, or a faint nova becomes feasible, as the lower dispersion concentrates the object's faint light, increasing the signal-to-noise ratio per pixel.\u003c\/p\u003e\n\u003cp\u003eThis grating is also essential for spectral classification. To determine if a star is a hot, blue O-type or a cool, red M-type, you need to see the overall shape of its blackbody curve and the presence of broad absorption features. The 300 l\/mm grating allows you to capture this full \"fingerprint\" in a single frame, making it a powerful tool for stellar astrophysics projects.\u003c\/p\u003e\n\u003c\/div\u003e\n\u003c\/div\u003e\n\u003c\/div\u003e\n\u003c\/li\u003e\n\u003cli\u003e\n\u003cdiv class=\"DAV-accordion\"\u003e\n\u003ch3 class=\"DAV-accordion-Q\"\u003eWhy would I choose the 300 l\/mm grating for my Lhires III when it comes with a 2400 l\/mm grating?\u003c\/h3\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion-A\"\u003e\n\u003cp\u003eYou would choose the \u003cstrong\u003e300 l\/mm grating\u003c\/strong\u003e when your scientific goal requires a wide spectral range rather than high resolution. The standard 2400 l\/mm grating is for detailed study of narrow spectral lines, while the 300 l\/mm grating is for capturing the entire visible spectrum of an object at once, which is necessary for spectral classification or studying objects with broad emission features like novae and quasars.\u003c\/p\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion\"\u003e\n\u003ch3 class=\"DAV-accordion-Q\"\u003eWhat is the main advantage of the 300 l\/mm Lhires III grating module?\u003c\/h3\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion-A\"\u003e\n\u003cp\u003eThe main advantage is \u003cstrong\u003espectral coverage\u003c\/strong\u003e. It allows your Lhires III to capture a much wider range of wavelengths in a single exposure compared to the standard high-resolution grating. This makes it possible to analyze the overall energy distribution of a star or capture the full spectrum of faint, extended objects.\u003c\/p\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion\"\u003e\n\u003ch3 class=\"DAV-accordion-Q\"\u003eIs the 300 l\/mm grating module for the Lhires III good for studying faint objects like comets?\u003c\/h3\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion-A\"\u003e\n\u003cp\u003eYes, it is an excellent choice. Because the 300 l\/mm grating has a lower dispersion, it concentrates the faint light from objects like \u003cstrong\u003ecomets, faint novae, or distant galaxies\u003c\/strong\u003e more effectively on your camera's sensor. This results in a higher signal-to-noise ratio, making it easier to obtain a usable spectrum from challenging targets.\u003c\/p\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion\"\u003e\n\u003ch3 class=\"DAV-accordion-Q\"\u003eHow does the 300 l\/mm grating affect the spectrum I can capture with my Lhires III and an 8\" SCT?\u003c\/h3\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion-A\"\u003e\n\u003cp\u003eWith an \u003cstrong\u003e8\" SCT\u003c\/strong\u003e, the 300 l\/mm grating will allow your Lhires III to function as a powerful survey and classification instrument. You will be able to capture the entire visible spectrum of moderately bright stars in a single shot, allowing you to classify them based on their overall spectral features (e.g., O, B, A, F, G, K, M types). This is a task that would be impossible with the narrow-band view of the standard 2400 l\/mm grating.\u003c\/p\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion\"\u003e\n\u003ch3 class=\"DAV-accordion-Q\"\u003eCan I use the 300 l\/mm grating for spectral classification of stars like Vega (Alpha Lyrae)?\u003c\/h3\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion-A\"\u003e\n\u003cp\u003eAbsolutely. The 300 l\/mm grating is perfect for this application. For a star like \u003cstrong\u003eVega (Alpha Lyrae)\u003c\/strong\u003e, an A0V-class star, this grating will allow you to easily capture the prominent, broad absorption lines of the Balmer series (Hydrogen-alpha, beta, gamma, etc.) that define its spectral type, all within a single image.\u003c\/p\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion\"\u003e\n\u003ch3 class=\"DAV-accordion-Q\"\u003eIs swapping the grating in the Lhires III difficult?\u003c\/h3\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion-A\"\u003e\n\u003cp\u003eThe grating module is designed for user installation, allowing you to switch between resolutions based on your observing targets for the night. While the process is straightforward, it requires care to avoid damaging the optical components. We strongly recommend consulting the official \u003cstrong\u003eLhires III user manual\u003c\/strong\u003e for detailed, step-by-step instructions before changing the grating.\u003c\/p\u003e\n\u003c\/div\u003e\n\u003c\/li\u003e\n\u003cli\u003e\n\u003ctable class=\"DAV-specifications\"\u003e\n\u003ctbody\u003e\n\u003ctr\u003e\n\u003ctd\u003eGrating Ruling\u003c\/td\u003e\n\u003ctd\u003e300 lines\/mm\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eCompatibility\u003c\/td\u003e\n\u003ctd\u003eShelyak Lhires III Spectroscope\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003c\/tbody\u003e\n\u003c\/table\u003e\n\u003c\/li\u003e\n\u003cli\u003e\n\u003cul class=\"DAV-grid\"\u003e\n\u003cli class=\"DAV-grid-item\"\u003e\n\u003cdiv\u003e\n\u003cp class=\"DAV-item-title\"\u003e300 l\/mm Grating Module for Lhires III\u003c\/p\u003e\n\u003cp class=\"DAV-item-subtitle\"\u003e× 1\u003c\/p\u003e\n\u003c\/div\u003e\n\u003c\/li\u003e\n\u003c\/ul\u003e\n\u003c\/li\u003e\n\u003cli\u003e\n\u003cul class=\"DAV-grid\"\u003e\n\u003cli class=\"DAV-grid-item\"\u003e\u003ca href=\"https:\/\/cdn.shopify.com\/s\/files\/1\/0753\/5280\/1565\/files\/Shelyak_Lhires_III_Manual.pdf\" target=\"_blank\"\u003e\u003csvg class=\"DAV-img-box\" viewbox=\"0 0 512 512\" xmlns=\"http:\/\/www.w3.org\/2000\/svg\"\u003e\u003cpath d=\"M0 64C0 28.7 28.7 0 64 0L224 0l0 128c0 17.7 14.3 32 32 32l128 0 0 144-208 0c-35.3 0-64 28.7-64 64l0 144-48 0c-35.3 0-64-28.7-64-64L0 64zm384 64l-128 0L256 0 384 128zM176 352l32 0c30.9 0 56 25.1 56 56s-25.1 56-56 56l-16 0 0 32c0 8.8-7.2 16-16 16s-16-7.2-16-16l0-48 0-80c0-8.8 7.2-16 16-16zm32 80c13.3 0 24-10.7 24-24s-10.7-24-24-24l-16 0 0 48 16 0zm96-80l32 0c26.5 0 48 21.5 48 48l0 64c0 26.5-21.5 48-48 48l-32 0c-8.8 0-16-7.2-16-16l0-128c0-8.8 7.2-16 16-16zm32 128c8.8 0 16-7.2 16-16l0-64c0-8.8-7.2-16-16-16l-16 0 0 96 16 0zm80-112c0-8.8 7.2-16 16-16l48 0c8.8 0 16 7.2 16 16s-7.2 16-16 16l-32 0 0 32 32 0c8.8 0 16 7.2 16 16s-7.2 16-16 16l-32 0 0 48c0 8.8-7.2 16-16 16s-16-7.2-16-16l0-64 0-64z\" fill=\"#0047a7\"\u003e\u003c\/path\u003e\u003c\/svg\u003e\n\u003cdiv\u003e\n\u003cp class=\"DAV-item-title\"\u003eShelyak Lhires III Manual\u003c\/p\u003e\n\u003c\/div\u003e\n\u003c\/a\u003e\u003c\/li\u003e\n\u003c\/ul\u003e\n\u003c\/li\u003e\n\u003cli\u003e\n\u003ca href=\"https:\/\/davidastro.com\/pages\/shelyak-warranty-policy\" rel=\"noopener\" target=\"_blank\"\u003eShelyak 1-Year Warranty\u003c\/a\u003e\n\u003c\/li\u003e\n\u003c\/ul\u003e","brand":"Shelyak","offers":[{"title":"Default Title","offer_id":52943043395869,"sku":"SHK-SE0008","price":1018.0,"currency_code":"CAD","in_stock":true}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0753\/5280\/1565\/files\/Shelyak-Grating-module-for-the-Lhires-III-2400-l-mm-1_bfdfdc51-9b7a-4e59-9b7a-94c104a85295.jpg?v=1789616219"},{"product_id":"shelyak-se0009","title":"Shelyak Grating module for the Lhires III - 150 l\/mm","description":"\u003cul class=\"DAV-feature-list\"\u003e\n\u003cli\u003e150 lines\/mm Grating\u003c\/li\u003e\n\u003cli\u003eLow Resolution \/ Wide Spectral Range\u003c\/li\u003e\n\u003cli\u003eDesigned for the Shelyak Lhires III Spectroscope\u003c\/li\u003e\n\u003cli\u003eEnables Faint Object Spectroscopy\u003c\/li\u003e\n\u003cli\u003eUser-Interchangeable Module\u003c\/li\u003e\n\u003c\/ul\u003e\n\u003c!-- more --\u003e\n\u003cul class=\"tabs\"\u003e\n\u003cli class=\"active\"\u003eDescription\u003c\/li\u003e\n\u003cli\u003eFAQ\u003c\/li\u003e\n\n\u003cli\u003eDownloads\u003c\/li\u003e\n\u003cli\u003eWarranty\u003c\/li\u003e\n\u003c\/ul\u003e\n\u003cul class=\"tabs-content\"\u003e\n\u003cli class=\"active\"\u003e\n\u003cdiv\u003e\n\u003cdiv class=\"DAV-bg-light\"\u003e\n\u003cdiv class=\"DAV-section-center\"\u003e\n\u003ch2\u003eGrating module for the Lhires III - 150 l\/mm\u003c\/h2\u003e\n\u003cp\u003eThis 150 lines\/mm grating module transforms the Shelyak Lhires III from a specialized high-resolution instrument into a versatile survey spectroscope. By replacing the standard 2400 l\/mm grating, you dramatically lower the dispersion to capture a much wider spectral range in a single exposure, opening up new targets for scientific analysis.\u003c\/p\u003e\n\u003c\/div\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-bg-light\"\u003e\n\u003cdiv class=\"DAV-section\"\u003e\n\u003ch3\u003eSurvey Mode for the Lhires III: The 150 l\/mm Advantage\u003c\/h3\u003e\n\u003cp\u003eThe core purpose of the Lhires III is high-resolution spectroscopy, but this requires bright targets and isolates a very narrow slice of the spectrum. The 150 l\/mm grating module intentionally trades that high resolution for a massive increase in spectral bandwidth and throughput, allowing you to analyze faint, extended, or continuum-source objects that are inaccessible with the standard grating.\u003c\/p\u003e\n\u003cp\u003eThis makes the 150 l\/mm module the ideal tool for rapid classification of transient events like supernovae and novae, studying the broad emission features of comets, or capturing the full visible spectrum of faint deep-sky objects. It effectively adds a \"survey mode\" to your Lhires III, expanding its research capabilities significantly.\u003c\/p\u003e\n\u003c\/div\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-bg-light\"\u003e\n\u003cdiv class=\"DAV-section\"\u003e\n\u003ch3\u003e150 l\/mm vs. 2400 l\/mm: Choosing the Right Grating for Your Target\u003c\/h3\u003e\n\u003cp\u003eSelecting the correct grating is critical for matching the instrument to your scientific goals. The two options serve fundamentally different purposes.\u003c\/p\u003e\n\u003cul\u003e\n\u003cli\u003e\n\u003cstrong\u003eStandard 2400 l\/mm Grating:\u003c\/strong\u003e This is for high-resolution work on bright stars. Use it to detect the subtle Doppler shifts in binary star systems, analyze the fine absorption lines in a stellar atmosphere (like the Sodium D-lines), or measure precise radial velocities. Its spectral range is very narrow.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003e150 l\/mm Grating Module:\u003c\/strong\u003e This is for low-resolution \"big picture\" spectroscopy. Use it to obtain a spectrum of a faint comet, classify a supernova by its broad spectral features, or monitor the spectral evolution of a variable star across the entire visible range at once.\u003c\/li\u003e\n\u003c\/ul\u003e\n\u003c\/div\u003e\n\u003c\/div\u003e\n\u003c\/div\u003e\n\u003c\/li\u003e\n\u003cli\u003e\n\u003cdiv class=\"DAV-accordion\"\u003e\n\u003ch3 class=\"DAV-accordion-Q\"\u003eWhat is the main application for the Shelyak 150 l\/mm grating module for the Lhires III?\u003c\/h3\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion-A\"\u003e\n\u003cp\u003eThe primary application is for low-resolution spectroscopy of faint or transient objects. It allows you to capture a wide spectral range in a single shot, which is essential for classifying objects like supernovae, analyzing the broad emission bands of comets, or studying faint nebulae.\u003c\/p\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion\"\u003e\n\u003ch3 class=\"DAV-accordion-Q\"\u003eHow does the 150 l\/mm grating change the data I can collect with my Lhires III?\u003c\/h3\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion-A\"\u003e\n\u003cp\u003eIt fundamentally changes the trade-off between spectral resolution and wavelength coverage. Instead of a very detailed view of a tiny part of the spectrum (like with the standard 2400 l\/mm grating), the \u003cstrong\u003e150 l\/mm grating\u003c\/strong\u003e provides a lower-detail view of a much wider portion of the spectrum. This is better for understanding the overall nature of an object rather than its fine atmospheric details.\u003c\/p\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion\"\u003e\n\u003ch3 class=\"DAV-accordion-Q\"\u003eDo I need to recalibrate my Lhires III when I switch to the 150 l\/mm grating?\u003c\/h3\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion-A\"\u003e\n\u003cp\u003eYes, absolutely. Any time you change the grating in a spectroscope, you must perform a new wavelength calibration. The dispersion, or how much the light is spread out per pixel, is completely different for the 150 l\/mm grating compared to the standard 2400 l\/mm grating. You will need to take new calibration frames with a reference lamp.\u003c\/p\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion\"\u003e\n\u003ch3 class=\"DAV-accordion-Q\"\u003eIs the 150 l\/mm grating suitable for classifying a newly discovered supernova like SN 2023ixf with an 11\" SCT?\u003c\/h3\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion-A\"\u003e\n\u003cp\u003eYes, this is an ideal use case. An 11\" SCT provides enough light-gathering power, and the \u003cstrong\u003e150 l\/mm grating\u003c\/strong\u003e provides the wide spectral coverage needed to identify the characteristic broad absorption lines (like Silicon II for a Type Ia) used for supernova classification. The standard 2400 l\/mm grating would be unsuitable for this task as it would only show a tiny, unidentifiable fraction of the spectrum.\u003c\/p\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion\"\u003e\n\u003ch3 class=\"DAV-accordion-Q\"\u003eCan I use the 150 l\/mm grating to study the changing tail composition of Comet C\/2022 E3 (ZTF)?\u003c\/h3\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion-A\"\u003e\n\u003cp\u003eThis is another excellent application. Cometary spectra are dominated by broad emission bands from molecules like C2 (the Swan bands) and CN. The \u003cstrong\u003e150 l\/mm grating\u003c\/strong\u003e allows you to capture all these features simultaneously to monitor how the comet's outgassing and composition evolve as it approaches and leaves the sun.\u003c\/p\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion\"\u003e\n\u003ch3 class=\"DAV-accordion-Q\"\u003eWhen should I use the standard 2400 l\/mm grating instead of this 150 l\/mm module?\u003c\/h3\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion-A\"\u003e\n\u003cp\u003eYou should use the standard \u003cstrong\u003e2400 l\/mm grating\u003c\/strong\u003e when your scientific goal requires very high spectral resolution for bright targets. This includes measuring precise radial velocity shifts from stellar wobble, studying the detailed profiles of spectral lines in Be stars, or resolving close spectroscopic binaries.\u003c\/p\u003e\n\u003c\/div\u003e\n\u003c\/li\u003e\n\n\u003cli\u003e\n\u003cul class=\"DAV-grid\"\u003e\n\u003cli class=\"DAV-grid-item\"\u003e\u003ca href=\"https:\/\/cdn.shopify.com\/s\/files\/1\/0753\/5280\/1565\/files\/Shelyak_Lhires_III_Manual.pdf\" target=\"_blank\"\u003e\u003csvg class=\"DAV-img-box\" viewbox=\"0 0 512 512\" xmlns=\"http:\/\/www.w3.org\/2000\/svg\"\u003e\u003cpath d=\"M0 64C0 28.7 28.7 0 64 0L224 0l0 128c0 17.7 14.3 32 32 32l128 0 0 144-208 0c-35.3 0-64 28.7-64 64l0 144-48 0c-35.3 0-64-28.7-64-64L0 64zm384 64l-128 0L256 0 384 128zM176 352l32 0c30.9 0 56 25.1 56 56s-25.1 56-56 56l-16 0 0 32c0 8.8-7.2 16-16 16s-16-7.2-16-16l0-48 0-80c0-8.8 7.2-16 16-16zm32 80c13.3 0 24-10.7 24-24s-10.7-24-24-24l-16 0 0 48 16 0zm96-80l32 0c26.5 0 48 21.5 48 48l0 64c0 26.5-21.5 48-48 48l-32 0c-8.8 0-16-7.2-16-16l0-128c0-8.8 7.2-16 16-16zm32 128c8.8 0 16-7.2 16-16l0-64c0-8.8-7.2-16-16-16l-16 0 0 96 16 0zm80-112c0-8.8 7.2-16 16-16l48 0c8.8 0 16 7.2 16 16s-7.2 16-16 16l-32 0 0 32 32 0c8.8 0 16 7.2 16 16s-7.2 16-16 16l-32 0 0 48c0 8.8-7.2 16-16 16s-16-7.2-16-16l0-64 0-64z\" fill=\"#0047a7\"\u003e\u003c\/path\u003e\u003c\/svg\u003e\n\u003cdiv\u003e\n\u003cp class=\"DAV-item-title\"\u003eShelyak Lhires III Manual\u003c\/p\u003e\n\u003c\/div\u003e\n\u003c\/a\u003e\u003c\/li\u003e\n\u003c\/ul\u003e\n\u003c\/li\u003e\n\u003cli\u003e\n\u003ca href=\"https:\/\/davidastro.com\/pages\/shelyak-warranty-policy\" rel=\"noopener\" target=\"_blank\"\u003eShelyak 1-Year Warranty\u003c\/a\u003e\n\u003c\/li\u003e\n\u003c\/ul\u003e","brand":"Shelyak","offers":[{"title":"Default Title","offer_id":52943043690781,"sku":"SHK-SE0009","price":1018.0,"currency_code":"CAD","in_stock":true}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0753\/5280\/1565\/files\/Shelyak-Grating-module-for-the-Lhires-III-2400-l-mm-1_4dbbeda5-5e16-4f2e-800a-130d89ab377d.jpg?v=1789616227"},{"product_id":"shelyak-se0116","title":"Shelyak Multiple Slit 15\/19\/23\/35 µm","description":"\u003cul class=\"DAV-feature-list\"\u003e\n\u003cli\u003eFour Selectable Slit Widths: 15µm, 19µm, 23µm, 35µm\u003c\/li\u003e\n\u003cli\u003eReflective Slit Design for Maximum Throughput\u003c\/li\u003e\n\u003cli\u003eCompatible with Shelyak LISA \u0026amp; Lhires III Spectroscopes\u003c\/li\u003e\n\u003cli\u003eCan be used with Sol'Ex for Stellar Observation (Requires Guiding Module)\u003c\/li\u003e\n\u003cli\u003eRequires Matching Slit Holder for Operation\u003c\/li\u003e\n\u003c\/ul\u003e\n\u003c!-- more --\u003e\n\u003cul class=\"tabs\"\u003e\n\u003cli class=\"active\"\u003eDescription\u003c\/li\u003e\n\u003cli\u003eFAQ\u003c\/li\u003e\n\u003cli\u003eSpecifications\u003c\/li\u003e\n\u003cli\u003eIn the Box\u003c\/li\u003e\n\u003cli\u003eDownloads\u003c\/li\u003e\n\u003cli\u003eWarranty\u003c\/li\u003e\n\u003c\/ul\u003e\n\u003cul class=\"tabs-content\"\u003e\n\u003cli class=\"active\"\u003e\n\u003cdiv\u003e\n\u003cdiv class=\"DAV-bg-light\"\u003e\n\u003cdiv class=\"DAV-section-center\"\u003e\n\u003ch2\u003eShelyak Multiple Slit 15\/19\/23\/35 µm\u003c\/h2\u003e\n\u003cp\u003eThis Shelyak Multiple Slit provides four selectable reflective slit widths—15 µm, 19 µm, 23 µm, and 35 µm—for direct integration with LISA and Lhires III spectroscopes. The 4 positions allow you to precisely balance spectral resolution against light throughput, with the 15 µm slit offering the highest resolution for bright targets and the 35 µm slit maximizing signal for faint objects.\u003c\/p\u003e\n\u003c\/div\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-bg-light\"\u003e\n\u003cdiv class=\"DAV-section\"\u003e\n\u003ch3\u003eFour Slit Options: 15, 19, 23, and 35 µm\u003c\/h3\u003e\n\u003cp\u003eThe core of spectroscopy is the trade-off between resolution and light gathering. This 4-position slit allows you to optimize your instrument for any target. Use the narrow 15 µm slit to resolve fine details in the spectra of bright stars, or switch to the wide 35 µm slit to capture enough photons from a faint galaxy to register a usable signal.\u003c\/p\u003e\n\u003cul\u003e\n\u003cli\u003e\n\u003cstrong\u003e15 µm \u0026amp; 19 µm:\u003c\/strong\u003e Ideal for high-resolution work on bright stars, planetary nebulae, and other high-surface-brightness targets where separating close spectral lines is the primary goal.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003e23 µm \u0026amp; 35 µm:\u003c\/strong\u003e Best for faint targets like nebulae, comets, and galaxies. These wider slits increase light throughput at the cost of resolution, making them essential for low-signal situations.\u003c\/li\u003e\n\u003c\/ul\u003e\n\u003c\/div\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-bg-light\"\u003e\n\u003cdiv class=\"DAV-section\"\u003e\n\u003ch3\u003eCompatibility: For LISA, Lhires III, and Sol'Ex Spectroscopes\u003c\/h3\u003e\n\u003cp\u003eDesigned as a standard component for Shelyak's high-resolution spectrographs, this slit seamlessly integrates with the LISA and Lhires III models. It can also be purchased as an additional unit to allow for rapid changes between different setups in the field. Please note that a matching slit holder for your specific spectroscope (LISA or Lhires III) is required for use.\u003c\/p\u003e\n\u003cp\u003eThis component can also be adapted for stellar observations with a Sol'Ex spectroscope. To use it in this configuration, the Shelyak guiding module is a mandatory accessory to ensure proper alignment and function.\u003c\/p\u003e\n\u003c\/div\u003e\n\u003c\/div\u003e\n\u003c\/div\u003e\n\u003c\/li\u003e\n\u003cli\u003e\n\u003cdiv class=\"DAV-accordion\"\u003e\n\u003ch3 class=\"DAV-accordion-Q\"\u003eWhich slit on the Multiple Slit should I use for a bright star like Vega (Alpha Lyrae)?\u003c\/h3\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion-A\"\u003e\n\u003cp\u003eFor a bright star like \u003cstrong\u003eVega\u003c\/strong\u003e, you should use the narrowest slits to achieve the highest spectral resolution. Start with the \u003cstrong\u003e15 µm\u003c\/strong\u003e or \u003cstrong\u003e19 µm\u003c\/strong\u003e positions. This will allow you to clearly separate fine absorption lines in the star's spectrum.\u003c\/p\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion\"\u003e\n\u003ch3 class=\"DAV-accordion-Q\"\u003eCan I use this Multiple Slit with my Shelyak Sol'Ex for solar observing?\u003c\/h3\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion-A\"\u003e\n\u003cp\u003eNo. While this slit is compatible with the Sol'Ex, it is intended for \u003cstrong\u003estellar observations\u003c\/strong\u003e only. For solar work, you should use the slit included with the Sol'Ex. Using this slit with a Sol'Ex for any target also requires the addition of the Shelyak guiding module.\u003c\/p\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion\"\u003e\n\u003ch3 class=\"DAV-accordion-Q\"\u003eDo I need a separate holder to use this Multiple Slit with my Lhires III?\u003c\/h3\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion-A\"\u003e\n\u003cp\u003e\u003cstrong\u003eYes, a matching slit holder is required.\u003c\/strong\u003e This slit module is designed to be installed into a holder specific to either the Lhires III or the LISA spectroscope. The holder is not included with the slit itself.\u003c\/p\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion\"\u003e\n\u003ch3 class=\"DAV-accordion-Q\"\u003eWhat is the benefit of the 35 µm slit on this Multiple Slit?\u003c\/h3\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion-A\"\u003e\n\u003cp\u003eThe \u003cstrong\u003e35 µm slit\u003c\/strong\u003e allows the maximum amount of light to pass through to the sensor. This is critical for obtaining a usable spectrum from very faint deep-sky objects, such as distant galaxies or diffuse nebulae, where collecting every possible photon is more important than achieving high resolution.\u003c\/p\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion\"\u003e\n\u003ch3 class=\"DAV-accordion-Q\"\u003eIs this Multiple Slit compatible with the Shelyak LISA spectroscope?\u003c\/h3\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion-A\"\u003e\n\u003cp\u003eYes, this is a standard slit for the Shelyak LISA spectroscope. However, you must pair it with the specific slit holder designed for the LISA to ensure correct installation and alignment.\u003c\/p\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion\"\u003e\n\u003ch3 class=\"DAV-accordion-Q\"\u003eWhy would I buy a second Multiple Slit 15\/19\/23\/35 µm?\u003c\/h3\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion-A\"\u003e\n\u003cp\u003ePurchasing an additional slit set allows you to have multiple holders ready for immediate use. This facilitates quick changes in the field, minimizing downtime and the risk of handling delicate optical components in the dark.\u003c\/p\u003e\n\u003c\/div\u003e\n\u003c\/li\u003e\n\u003cli\u003e\n\u003ctable class=\"DAV-specifications\"\u003e\n\u003ctbody\u003e\n\u003ctr\u003e\n\u003ctd\u003eSlit Widths\u003c\/td\u003e\n\u003ctd\u003e15 µm, 19 µm, 23 µm, 35 µm\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eNumber of Positions\u003c\/td\u003e\n\u003ctd\u003e4\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eSlit Type\u003c\/td\u003e\n\u003ctd\u003eReflective (Mirror)\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003ePrimary Compatibility\u003c\/td\u003e\n\u003ctd\u003eShelyak LISA, Shelyak Lhires III\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eSecondary Compatibility\u003c\/td\u003e\n\u003ctd\u003eShelyak Sol'Ex (for stellar use, requires guiding module)\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003c\/tbody\u003e\n\u003c\/table\u003e\n\u003c\/li\u003e\n\u003cli\u003e\n\u003cul class=\"DAV-grid\"\u003e\n\u003cli class=\"DAV-grid-item\"\u003e\n\u003cdiv\u003e\n\u003cp class=\"DAV-item-title\"\u003eMultiple Slit 15\/19\/23\/35 µm\u003c\/p\u003e\n\u003cp class=\"DAV-item-subtitle\"\u003e× 1\u003c\/p\u003e\n\u003c\/div\u003e\n\u003c\/li\u003e\n\u003c\/ul\u003e\n\u003c\/li\u003e\n\u003cli\u003e\n\u003cul class=\"DAV-grid\"\u003e\n\u003cli class=\"DAV-grid-item\"\u003e\u003ca href=\"https:\/\/cdn.shopify.com\/s\/files\/1\/0753\/5280\/1565\/files\/Shelyak_Lhires_III_Manual.pdf\" target=\"_blank\"\u003e\u003csvg class=\"DAV-img-box\" viewbox=\"0 0 512 512\" xmlns=\"http:\/\/www.w3.org\/2000\/svg\"\u003e\u003cpath d=\"M0 64C0 28.7 28.7 0 64 0L224 0l0 128c0 17.7 14.3 32 32 32l128 0 0 144-208 0c-35.3 0-64 28.7-64 64l0 144-48 0c-35.3 0-64-28.7-64-64L0 64zm384 64l-128 0L256 0 384 128zM176 352l32 0c30.9 0 56 25.1 56 56s-25.1 56-56 56l-16 0 0 32c0 8.8-7.2 16-16 16s-16-7.2-16-16l0-48 0-80c0-8.8 7.2-16 16-16zm32 80c13.3 0 24-10.7 24-24s-10.7-24-24-24l-16 0 0 48 16 0zm96-80l32 0c26.5 0 48 21.5 48 48l0 64c0 26.5-21.5 48-48 48l-32 0c-8.8 0-16-7.2-16-16l0-128c0-8.8 7.2-16 16-16zm32 128c8.8 0 16-7.2 16-16l0-64c0-8.8-7.2-16-16-16l-16 0 0 96 16 0zm80-112c0-8.8 7.2-16 16-16l48 0c8.8 0 16 7.2 16 16s-7.2 16-16 16l-32 0 0 32 32 0c8.8 0 16 7.2 16 16s-7.2 16-16 16l-32 0 0 48c0 8.8-7.2 16-16 16s-16-7.2-16-16l0-64 0-64z\" fill=\"#0047a7\"\u003e\u003c\/path\u003e\u003c\/svg\u003e\n\u003cdiv\u003e\n\u003cp class=\"DAV-item-title\"\u003eShelyak Lhires III Manual\u003c\/p\u003e\n\u003c\/div\u003e\n\u003c\/a\u003e\u003c\/li\u003e\n\u003c\/ul\u003e\n\u003c\/li\u003e\n\u003cli\u003e\n\u003ca href=\"https:\/\/davidastro.com\/pages\/shelyak-warranty-policy\" rel=\"noopener\" target=\"_blank\"\u003eShelyak 1-Year Warranty\u003c\/a\u003e\n\u003c\/li\u003e\n\u003c\/ul\u003e","brand":"Shelyak","offers":[{"title":"Default Title","offer_id":52943046312221,"sku":"SHK-SE0116","price":313.0,"currency_code":"CAD","in_stock":true}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0753\/5280\/1565\/files\/Shelyak-Multiple-slit-15-19-23-35-m-1_f076e588-6b6d-443e-b1eb-45149470cc2b.jpg?v=1789616293"},{"product_id":"shelyak-se0121","title":"Shelyak Grating module for the Lhires III - 1800 l\/mm","description":"\u003cul class=\"DAV-feature-list\"\u003e\n\u003cli\u003e\n\u003cstrong\u003eGrating Ruling:\u003c\/strong\u003e 1800 lines\/mm\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eCompatibility:\u003c\/strong\u003e Shelyak Lhires III Spectroscope\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eFunction:\u003c\/strong\u003e Alternative module to change native resolution\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eUse Case:\u003c\/strong\u003e Wider spectral coverage at lower resolution\u003c\/li\u003e\n\u003c\/ul\u003e\n\u003c!-- more --\u003e\n\u003cul class=\"tabs\"\u003e\n\u003cli class=\"active\"\u003eDescription\u003c\/li\u003e\n\u003cli\u003eFAQ\u003c\/li\u003e\n\n\u003cli\u003eDownloads\u003c\/li\u003e\n\u003cli\u003eWarranty\u003c\/li\u003e\n\u003c\/ul\u003e\n\n\u003cul class=\"tabs-content\"\u003e\n\u003cli class=\"active\"\u003e\n\u003cdiv\u003e\n  \u003cdiv class=\"DAV-bg-light\"\u003e\n    \u003cdiv class=\"DAV-section-center\"\u003e\n      \u003ch2\u003eGrating module for the Lhires III - 1800 l\/mm\u003c\/h2\u003e\n      \u003cp\u003eThis interchangeable grating module provides a ruling of 1800 lines\/mm, specifically designed to alter the native high-resolution capabilities of the Shelyak Lhires III spectroscope. It allows you to trade the maximum resolving power of the standard 2400 l\/mm grating for a significantly wider spectral window in a single exposure.\u003c\/p\u003e\n    \u003c\/div\u003e\n  \u003c\/div\u003e\n\n  \u003cdiv class=\"DAV-bg-light\"\u003e\n    \u003cdiv class=\"DAV-section\"\u003e\n      \u003ch3\u003eThe 1800 l\/mm Grating: Trading Resolution for Spectral Range\u003c\/h3\u003e\n      \u003cp\u003eIn spectroscopy, there is a fundamental trade-off between resolution and spectral coverage. This 1800 l\/mm grating module for the Lhires III is engineered for situations where capturing a broader range of wavelengths is more critical than achieving the highest possible resolution. By decreasing the line density from the standard 2400 l\/mm, this grating disperses light less, fitting more of the spectrum onto your camera sensor.\u003c\/p\u003e\n      \u003cp\u003eThis makes the 1800 l\/mm grating ideal for analyzing objects with broad emission or absorption features, such as supernovae (SNe), comets, or cataclysmic variable stars. It's the right choice when the scientific goal is classification or monitoring changes across a wide spectral range, rather than measuring the precise radial velocity of a single spectral line.\u003c\/p\u003e\n    \u003c\/div\u003e\n  \u003c\/div\u003e\n\n  \u003cdiv class=\"DAV-bg-light\"\u003e\n    \u003cdiv class=\"DAV-section\"\u003e\n      \u003ch3\u003eLhires III 1800 l\/mm vs. Standard 2400 l\/mm Grating\u003c\/h3\u003e\n      \u003cp\u003eThe Lhires III spectroscope ships with a 2400 l\/mm grating, which is optimized for high-resolution studies of specific, narrow spectral regions. This alternate 1800 l\/mm module extends the instrument's capabilities, turning it into a more adaptable research tool.\u003c\/p\u003e\n      \u003cul\u003e\n        \u003cli\u003e\n\u003cstrong\u003eStandard 2400 l\/mm Grating:\u003c\/strong\u003e Use this for maximum resolving power. It excels at splitting close binary star lines, measuring the Doppler shift in stellar spectra, or studying the fine structure of nebular emission lines like H-alpha and OIII.\u003c\/li\u003e\n        \u003cli\u003e\n\u003cstrong\u003eOptional 1800 l\/mm Grating:\u003c\/strong\u003e Choose this module for survey work or for targets where context is key. It allows you to capture, for example, the H-alpha, H-beta, and H-gamma lines of a Be star in a single frame, something not possible with the higher-resolution grating.\u003c\/li\u003e\n      \u003c\/ul\u003e\n    \u003c\/div\u003e\n  \u003c\/div\u003e\n\n\u003c\/div\u003e\n\u003c\/li\u003e\n\n\u003cli\u003e\n  \u003cdiv class=\"DAV-accordion\"\u003e\n    \u003ch3 class=\"DAV-accordion-Q\"\u003eWhy would I choose the 1800 l\/mm grating for my Lhires III instead of the standard 2400 l\/mm?\u003c\/h3\u003e\n  \u003c\/div\u003e\n  \u003cdiv class=\"DAV-accordion-A\"\u003e\n    \u003cp\u003eYou would choose the \u003cstrong\u003e1800 l\/mm grating\u003c\/strong\u003e when your primary goal is to capture a wider range of wavelengths in a single exposure. The standard \u003cstrong\u003e2400 l\/mm grating\u003c\/strong\u003e offers higher resolution but sees a smaller piece of the spectrum. The 1800 l\/mm module is for applications like classifying supernovae or studying comets, where broad spectral features are more important than resolving fine details.\u003c\/p\u003e\n  \u003c\/div\u003e\n  \u003cdiv class=\"DAV-accordion\"\u003e\n    \u003ch3 class=\"DAV-accordion-Q\"\u003eWhat astronomical targets are best for the Lhires III with the 1800 l\/mm grating?\u003c\/h3\u003e\n  \u003c\/div\u003e\n  \u003cdiv class=\"DAV-accordion-A\"\u003e\n    \u003cp\u003eThe 1800 l\/mm grating is ideal for targets with broad or multiple, widely-spaced spectral features. Good examples include:\u003c\/p\u003e\n    \u003cul\u003e\n      \u003cli\u003e\n\u003cstrong\u003eSupernovae (SNe):\u003c\/strong\u003e For classification based on broad silicon or hydrogen absorption lines.\u003c\/li\u003e\n      \u003cli\u003e\n\u003cstrong\u003eComets:\u003c\/strong\u003e To capture multiple molecular emission bands (like C2) simultaneously.\u003c\/li\u003e\n      \u003cli\u003e\n\u003cstrong\u003eBe Stars:\u003c\/strong\u003e To observe the profile of hydrogen Balmer lines (H-alpha, H-beta, etc.) in one frame.\u003c\/li\u003e\n      \u003cli\u003e\n\u003cstrong\u003eVariable Stars:\u003c\/strong\u003e For general spectrophotometry across a wide passband.\u003c\/li\u003e\n    \u003c\/ul\u003e\n  \u003c\/div\u003e\n    \u003cdiv class=\"DAV-accordion\"\u003e\n    \u003ch3 class=\"DAV-accordion-Q\"\u003eIs the 1800 l\/mm grating a direct replacement for the Lhires III's original grating?\u003c\/h3\u003e\n  \u003c\/div\u003e\n  \u003cdiv class=\"DAV-accordion-A\"\u003e\n    \u003cp\u003eYes, this is a fully compatible, interchangeable module designed by Shelyak specifically for the Lhires III spectroscope. It is intended to be swapped with the standard 2400 l\/mm grating to change the instrument's optical characteristics based on your observing target.\u003c\/p\u003e\n  \u003c\/div\u003e\n  \u003cdiv class=\"DAV-accordion\"\u003e\n    \u003ch3 class=\"DAV-accordion-Q\"\u003eWill the Lhires III 1800 l\/mm grating let me capture the spectrum of a star like Vega (Alpha Lyrae) in one shot?\u003c\/h3\u003e\n  \u003c\/div\u003e\n  \u003cdiv class=\"DAV-accordion-A\"\u003e\n    \u003cp\u003eThe 1800 l\/mm grating provides a much wider field of view than the standard 2400 l\/mm grating, making it better suited for capturing broad stellar spectra. While the exact spectral range you can capture depends on your camera's sensor size and the specific wavelength you center on, this grating is the correct choice for projects that require observing multiple hydrogen Balmer lines in A-type stars like Vega in a single frame.\u003c\/p\u003e\n  \u003c\/div\u003e\n  \u003cdiv class=\"DAV-accordion\"\u003e\n    \u003ch3 class=\"DAV-accordion-Q\"\u003eHow does the 1800 l\/mm grating affect the brightness of the spectrum from my Lhires III?\u003c\/h3\u003e\n  \u003c\/div\u003e\n  \u003cdiv class=\"DAV-accordion-A\"\u003e\n    \u003cp\u003eBy dispersing starlight over a smaller area (lower dispersion), the 1800 l\/mm grating can produce a brighter continuum in the resulting spectrum compared to the 2400 l\/mm grating, assuming equal exposure time and conditions. This can be advantageous for obtaining a better signal-to-noise ratio on the overall spectrum of fainter objects.\u003c\/p\u003e\n  \u003c\/div\u003e\n    \u003cdiv class=\"DAV-accordion\"\u003e\n    \u003ch3 class=\"DAV-accordion-Q\"\u003eDoes installing the 1800 l\/mm grating on the Lhires III require recalibration?\u003c\/h3\u003e\n  \u003c\/div\u003e\n  \u003cdiv class=\"DAV-accordion-A\"\u003e\n    \u003cp\u003eYes, absolutely. Any time you change the diffraction grating in a spectroscope, you change the instrument's dispersion (how many angstroms per pixel). You will need to perform a new spectral calibration using a calibration lamp to accurately measure wavelengths with the 1800 l\/mm grating installed.\u003c\/p\u003e\n  \u003c\/div\u003e\n\u003c\/li\u003e\n\n\u003cli\u003e\n\u003cul class=\"DAV-grid\"\u003e\n\u003cli class=\"DAV-grid-item\"\u003e\u003ca href=\"https:\/\/cdn.shopify.com\/s\/files\/1\/0753\/5280\/1565\/files\/Shelyak_Lhires_III_Manual.pdf\" target=\"_blank\"\u003e\u003csvg class=\"DAV-img-box\" viewbox=\"0 0 512 512\" xmlns=\"http:\/\/www.w3.org\/2000\/svg\"\u003e\u003cpath d=\"M0 64C0 28.7 28.7 0 64 0L224 0l0 128c0 17.7 14.3 32 32 32l128 0 0 144-208 0c-35.3 0-64 28.7-64 64l0 144-48 0c-35.3 0-64-28.7-64-64L0 64zm384 64l-128 0L256 0 384 128zM176 352l32 0c30.9 0 56 25.1 56 56s-25.1 56-56 56l-16 0 0 32c0 8.8-7.2 16-16 16s-16-7.2-16-16l0-48 0-80c0-8.8 7.2-16 16-16zm32 80c13.3 0 24-10.7 24-24s-10.7-24-24-24l-16 0 0 48 16 0zm96-80l32 0c26.5 0 48 21.5 48 48l0 64c0 26.5-21.5 48-48 48l-32 0c-8.8 0-16-7.2-16-16l0-128c0-8.8 7.2-16 16-16zm32 128c8.8 0 16-7.2 16-16l0-64c0-8.8-7.2-16-16-16l-16 0 0 96 16 0zm80-112c0-8.8 7.2-16 16-16l48 0c8.8 0 16 7.2 16 16s-7.2 16-16 16l-32 0 0 32 32 0c8.8 0 16 7.2 16 16s-7.2 16-16 16l-32 0 0 48c0 8.8-7.2 16-16 16s-16-7.2-16-16l0-64 0-64z\" fill=\"#0047a7\"\u003e\u003c\/path\u003e\u003c\/svg\u003e\n\u003cdiv\u003e\n\u003cp class=\"DAV-item-title\"\u003eShelyak Lhires III Manual\u003c\/p\u003e\n\u003c\/div\u003e\n\u003c\/a\u003e\u003c\/li\u003e\n\u003c\/ul\u003e\n\u003c\/li\u003e\n\n\u003cli\u003e\n\u003ca href=\"https:\/\/davidastro.com\/pages\/shelyak-warranty-policy\" rel=\"noopener\" target=\"_blank\"\u003eShelyak 1-Year Warranty\u003c\/a\u003e\n\u003c\/li\u003e\n\u003c\/ul\u003e","brand":"Shelyak","offers":[{"title":"Default Title","offer_id":52943046607133,"sku":"SHK-SE0121","price":1018.0,"currency_code":"CAD","in_stock":true}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0753\/5280\/1565\/files\/Shelyak-Grating-module-for-the-Lhires-III-2400-l-mm-1_615c59cc-77ae-4187-b3f8-b440ca16be11.jpg?v=1789616301"},{"product_id":"shelyak-se0122","title":"Shelyak Wide Slit Plate: 50\/75\/100 µm and 19 µm Hole","description":"\u003cul class=\"DAV-feature-list\"\u003e\n\u003cli\u003eFour selectable apertures on a single plate\u003c\/li\u003e\n\u003cli\u003eWide slits: 50 µm, 75 µm, and 100 µm\u003c\/li\u003e\n\u003cli\u003eCalibration aperture: 19 µm hole\u003c\/li\u003e\n\u003cli\u003eCompatible with Shelyak Lhires III \u0026amp; LISA Spectroscopes\u003c\/li\u003e\n\u003cli\u003eRequires corresponding slit holder (sold separately)\u003c\/li\u003e\n\u003c\/ul\u003e\n\u003c!-- more --\u003e\n\u003cul class=\"tabs\"\u003e\n\u003cli class=\"active\"\u003eDescription\u003c\/li\u003e\n\u003cli\u003eFAQ\u003c\/li\u003e\n\u003cli\u003eWarranty\u003c\/li\u003e\n\u003c\/ul\u003e\n\u003cul class=\"tabs-content\"\u003e\n\u003cli class=\"active\"\u003e\n\u003cdiv\u003e\n\u003cdiv class=\"DAV-bg-light\"\u003e\n\u003cdiv class=\"DAV-section-center\"\u003e\n\u003ch2\u003eShelyak Wide Slit Plate: 50\/75\/100 µm and 19 µm Hole\u003c\/h2\u003e\n\u003cp\u003eThis interchangeable plate for Shelyak LISA and Lhires III spectroscopes offers four apertures on a single rotating support, featuring three wide slits at 50 µm, 75 µm, and 100 µm. A central 19 µm hole is also included, designed specifically for precise instrument adjustment and focusing.\u003c\/p\u003e\n\u003c\/div\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-bg-light\"\u003e\n\u003cdiv class=\"DAV-section\"\u003e\n\u003ch3\u003eWide Slits for Faint Targets: 50 µm, 75 µm, and 100 µm Options\u003c\/h3\u003e\n\u003cp\u003eThe primary challenge when analyzing faint deep-sky objects is photon starvation. This plate provides 50 µm, 75 µm, and 100 µm slits that significantly increase light throughput compared to standard narrow slits. While this comes at the cost of spectral resolution, it is a necessary trade-off for capturing usable spectra from dim galaxies, faint comets, or distant quasars where maximizing signal is the priority. You can easily switch between slits by rotating the square support plate.\u003c\/p\u003e\n\u003c\/div\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-bg-light\"\u003e\n\u003cdiv class=\"DAV-section\"\u003e\n\u003ch3\u003ePrecision Calibration: The 19 µm Reference Hole\u003c\/h3\u003e\n\u003cp\u003eAchieving sharp focus and perfect alignment is critical for accurate spectroscopy. This plate includes a 19 µm hole that creates a perfectly round, star-like point source for calibration. By centering your target star in this hole, you can precisely adjust the spectroscope's focus and alignment before switching to a wider slit for your science observation. The reflective surface around the apertures aids in guiding by making the star clearly visible for accurate centering.\u003c\/p\u003e\n\u003c\/div\u003e\n\u003c\/div\u003e\n\u003c\/div\u003e\n\u003c\/li\u003e\n\u003cli\u003e\n\u003cdiv class=\"DAV-accordion\"\u003e\n\u003ch3 class=\"DAV-accordion-Q\"\u003eWhat is the purpose of the different slit sizes (50, 75, 100 µm) on this Shelyak slit plate?\u003c\/h3\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion-A\"\u003e\n\u003cp\u003eThe wider slits are designed to increase light throughput for spectroscopic analysis of faint objects. The \u003cstrong\u003e50 µm, 75 µm, and 100 µm slits\u003c\/strong\u003e allow more photons to reach the sensor, which is essential for targets like dim galaxies or comets. This comes at the expense of spectral resolution; a wider slit results in broader spectral lines.\u003c\/p\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion\"\u003e\n\u003ch3 class=\"DAV-accordion-Q\"\u003eHow do I use the 19 µm hole on the Lhires III wide slit plate?\u003c\/h3\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion-A\"\u003e\n\u003cp\u003eThe \u003cstrong\u003e19 µm hole\u003c\/strong\u003e serves as a high-precision tool for calibration and focusing. By placing a bright star in this small, circular aperture, you can accurately adjust the spectroscope's focus to achieve the sharpest possible spectral lines. Once focused, you can rotate the plate to a wider slit for your actual observation.\u003c\/p\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion\"\u003e\n\u003ch3 class=\"DAV-accordion-Q\"\u003eWhen should I use the 100 µm slit on my LISA spectroscope for observing a faint quasar like 3C 273?\u003c\/h3\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion-A\"\u003e\n\u003cp\u003eFor an extremely faint target like the quasar 3C 273, the \u003cstrong\u003e100 µm slit\u003c\/strong\u003e is the ideal choice. It provides the maximum possible light throughput, ensuring you can capture a detectable signal. While the spectral resolution will be lower, collecting enough photons to identify key features like redshifted emission lines is the primary goal for such a challenging object.\u003c\/p\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion\"\u003e\n\u003ch3 class=\"DAV-accordion-Q\"\u003eWhich slit should I choose for measuring the Doppler shift of a bright star like Vega (Alpha Lyrae) with my Lhires III?\u003c\/h3\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion-A\"\u003e\n\u003cp\u003eFor a bright star like Vega, maximizing resolution is more important than light gathering. Therefore, this wide slit plate may not be the optimal choice. You would typically use a much narrower slit (e.g., 15 or 23 µm) to achieve the high resolution needed to detect subtle Doppler shifts in the star's spectral lines. This plate is specifically designed for faint-object spectroscopy where throughput is critical.\u003c\/p\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion\"\u003e\n\u003ch3 class=\"DAV-accordion-Q\"\u003eIs a separate slit holder required for this Shelyak wide slit plate?\u003c\/h3\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion-A\"\u003e\n\u003cp\u003eYes. This slit plate is an insert and \u003cstrong\u003emust be combined with the matching slit holder\u003c\/strong\u003e for your specific spectroscope, whether it is the Shelyak LISA or Lhires III. The holder is not included with this plate.\u003c\/p\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion\"\u003e\n\u003ch3 class=\"DAV-accordion-Q\"\u003eHow do I switch between the 19 µm hole and the 100 µm slit?\u003c\/h3\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion-A\"\u003e\n\u003cp\u003eSwitching between apertures is straightforward. The four apertures (19 µm hole, 50 µm, 75 µm, and 100 µm slits) are mounted on a single square plate that can be \u003cstrong\u003emanually rotated\u003c\/strong\u003e to place the desired slit or hole into the optical path.\u003c\/p\u003e\n\u003c\/div\u003e\n\u003c\/li\u003e\n\n\u003cli\u003e\n\u003ca href=\"https:\/\/davidastro.com\/pages\/shelyak-warranty-policy\" rel=\"noopener\" target=\"_blank\"\u003eShelyak 1-Year Warranty\u003c\/a\u003e\n\u003c\/li\u003e\n\u003c\/ul\u003e","brand":"Shelyak","offers":[{"title":"Default Title","offer_id":52943046934813,"sku":"SHK-SE0122","price":339.0,"currency_code":"CAD","in_stock":true}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0753\/5280\/1565\/files\/Shelyak-Wide-slit-50-75-100-m-and-hole-19-m-1_322f835a-c526-42d6-b9cd-b30b4ab0c470.jpg?v=1789616309"},{"product_id":"shelyak-se0145","title":"Shelyak Photometric Slit 23\/200µm for Alpy 600 \u0026 UVEX","description":"\u003cul class=\"DAV-feature-list\"\u003e\n\u003cli\u003eDual slit design with 23µm and 200µm widths\u003c\/li\u003e\n\u003cli\u003eEnables high-resolution spectroscopy and spectrophotometry\u003c\/li\u003e\n\u003cli\u003eDesigned for Shelyak Alpy 600 and UVEX spectroscopes\u003c\/li\u003e\n\u003cli\u003eRequires the Alpy Guiding Module for operation\u003c\/li\u003e\n\u003c\/ul\u003e\n\u003c!-- more --\u003e\n\u003cul class=\"tabs\"\u003e\n\u003cli class=\"active\"\u003eDescription\u003c\/li\u003e\n\u003cli\u003eFAQ\u003c\/li\u003e\n\u003cli\u003eSpecifications\u003c\/li\u003e\n\u003cli\u003eWarranty\u003c\/li\u003e\n\u003c\/ul\u003e\n\u003cul class=\"tabs-content\"\u003e\n\u003cli class=\"active\"\u003e\n\u003cdiv\u003e\n\u003cdiv class=\"DAV-bg-light\"\u003e\n\u003cdiv class=\"DAV-section-center\"\u003e\n\u003ch2\u003ePhotometric Slit 23\/200µm for Alpy 600 \u0026amp; UVEX\u003c\/h2\u003e\n\u003cp\u003eThis Photometric Slit for Alpy 600 and UVEX spectroscopes enables true spectrophotometry by integrating two distinct apertures in a single component: a narrow 23µm slit for maximum resolution and a wide 200µm slit for capturing total stellar flux.\u003c\/p\u003e\n\u003c\/div\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-bg-light\"\u003e\n\u003cdiv class=\"DAV-section\"\u003e\n\u003ch3\u003eThe 23µm \/ 200µm Slit: A Dual-Purpose Tool for Spectrophotometry\u003c\/h3\u003e\n\u003cp\u003eThis accessory allows you to switch between two fundamental modes of spectroscopic observation without changing hardware. The 23µm slit provides the narrowest aperture, maximizing the spectral resolution of your Alpy 600 or UVEX to resolve fine details in stellar spectra. When your goal is to measure the precise brightness of an object across different wavelengths—true spectrophotometry—the wider 200µm slit ensures that all the light from the star enters the spectroscope, even in moments of poor seeing, for an accurate flux measurement.\u003c\/p\u003e\n\u003c\/div\u003e\n\u003c\/div\u003e\n\u003c\/div\u003e\n\u003c\/li\u003e\n\u003cli\u003e\n\u003cdiv class=\"DAV-accordion\"\u003e\n\u003ch3 class=\"DAV-accordion-Q\"\u003eWhat is the purpose of the dual slits on the 23\/200µm Photometric Slit?\u003c\/h3\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion-A\"\u003e\n\u003cp\u003eThe two slits serve two different scientific goals. The narrow \u003cstrong\u003e23µm slit\u003c\/strong\u003e is used to achieve the highest possible spectral resolution for detecting fine absorption or emission lines. The wide \u003cstrong\u003e200µm slit\u003c\/strong\u003e is used for spectrophotometry, where the goal is to capture all of a star's light to accurately measure its brightness, sacrificing some resolution for photometric precision.\u003c\/p\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion\"\u003e\n\u003ch3 class=\"DAV-accordion-Q\"\u003eWhen should I use the 23µm slit with my Alpy 600?\u003c\/h3\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion-A\"\u003e\n\u003cp\u003eUse the 23µm slit when your primary objective is resolving detail in a spectrum. This is ideal for classifying star types, identifying chemical compositions, or measuring the doppler shift of spectral lines in objects like binary stars or quasars.\u003c\/p\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion\"\u003e\n\u003ch3 class=\"DAV-accordion-Q\"\u003eWhen is the 200µm slit the right choice for the Photometric Slit?\u003c\/h3\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion-A\"\u003e\n\u003cp\u003eThe 200µm slit is essential for spectrophotometry. If you are studying variable stars, supernovae, or any object where you need to create an accurate spectral energy distribution curve, the wide slit ensures you are measuring the total energy output of the star without light loss at the aperture.\u003c\/p\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion\"\u003e\n\u003ch3 class=\"DAV-accordion-Q\"\u003eIs this Photometric Slit compatible with all Shelyak spectrographs?\u003c\/h3\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion-A\"\u003e\n\u003cp\u003eNo, this slit is specifically designed for use with the \u003cstrong\u003eShelyak Alpy 600\u003c\/strong\u003e and \u003cstrong\u003eShelyak UVEX\u003c\/strong\u003e spectroscope models. It is not compatible with other instruments like the Lhires III or LISA.\u003c\/p\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion\"\u003e\n\u003ch3 class=\"DAV-accordion-Q\"\u003eDo I need other accessories to use the 23\/200µm Photometric Slit?\u003c\/h3\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion-A\"\u003e\n\u003cp\u003eYes, this photometric slit must be used with the \u003cstrong\u003eAlpy Guiding Module\u003c\/strong\u003e. The guiding module is required to position the target star accurately on the desired slit and maintain that position during an exposure.\u003c\/p\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion\"\u003e\n\u003ch3 class=\"DAV-accordion-Q\"\u003eHow does the 200µm slit on the Photometric Slit help with poor seeing?\u003c\/h3\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion-A\"\u003e\n\u003cp\u003eAtmospheric turbulence (seeing) causes a star's image to move and swell. A narrow slit can block some of this light as the star image shifts, leading to an inaccurate brightness measurement. The wide 200µm slit provides a large enough opening to contain the entire star image even under poor seeing conditions, ensuring all its light enters the spectroscope for a valid photometric reading.\u003c\/p\u003e\n\u003c\/div\u003e\n\u003c\/li\u003e\n\u003cli\u003e\n\u003ctable class=\"DAV-specifications\"\u003e\n\u003ctbody\u003e\n\u003ctr\u003e\n\u003ctd\u003eSlit Widths\u003c\/td\u003e\n\u003ctd\u003e23µm (High Resolution) \/ 200µm (Photometry)\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003ePrimary Function\u003c\/td\u003e\n\u003ctd\u003eSpectrophotometry \u0026amp; High-Resolution Spectroscopy\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eCompatibility\u003c\/td\u003e\n\u003ctd\u003eShelyak Alpy 600, Shelyak UVEX\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eRequired Accessory\u003c\/td\u003e\n\u003ctd\u003eAlpy Guiding Module\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003c\/tbody\u003e\n\u003c\/table\u003e\n\u003c\/li\u003e\n\n\u003cli\u003e\u003ca href=\"https:\/\/davidastro.com\/pages\/shelyak-warranty-policy\" rel=\"noopener\" target=\"_blank\"\u003eShelyak 1-Year Warranty\u003c\/a\u003e\u003c\/li\u003e\n\u003c\/ul\u003e","brand":"Shelyak","offers":[{"title":"Default Title","offer_id":52943048638749,"sku":"SHK-SE0145","price":305.0,"currency_code":"CAD","in_stock":true}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0753\/5280\/1565\/files\/Shelyak-Photometric-slit-23-200-m-1_d73fed93-587d-42fe-8a9a-5716c60391fd.jpg?v=1789616359"},{"product_id":"shelyak-se0150","title":"Shelyak Alpy \u0026 UVEX 35 µm slit","description":"\u003cul class=\"DAV-feature-list\"\u003e\n\u003cli\u003e35 µm Precision Slit Width\u003c\/li\u003e\n\u003cli\u003eIntegrated Guiding Mirror Surface\u003c\/li\u003e\n\u003cli\u003eCompatible with Shelyak Alpy \u0026amp; UVEX Spectrographs\u003c\/li\u003e\n\u003c\/ul\u003e\n\u003c!-- more --\u003e\n\u003cul class=\"tabs\"\u003e\n\u003cli class=\"active\"\u003eDescription\u003c\/li\u003e\n\u003cli\u003eFAQ\u003c\/li\u003e\n\u003cli\u003eSpecifications\u003c\/li\u003e\n\u003cli\u003eIn the Box\u003c\/li\u003e\n\u003cli\u003eDownloads\u003c\/li\u003e\n\u003cli\u003eWarranty\u003c\/li\u003e\n\u003c\/ul\u003e\n\u003cul class=\"tabs-content\"\u003e\n\u003cli class=\"active\"\u003e\n\u003cdiv\u003e\n\u003cdiv class=\"DAV-bg-light\"\u003e\n\u003cdiv class=\"DAV-section-center\"\u003e\n\u003ch2\u003eAlpy \u0026amp; UVEX 35 µm slit\u003c\/h2\u003e\n\u003cp\u003eThe Alpy \u0026amp; UVEX 35 µm slit is a core component for Shelyak spectrographs, functioning as both a precision entrance aperture and a guiding mirror. Its 35 µm width strikes a versatile balance between spectral resolution and light throughput, making it a standard choice for a wide range of astronomical targets.\u003c\/p\u003e\n\u003c\/div\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-bg-light\"\u003e\n\u003cdiv class=\"DAV-section\"\u003e\n\u003ch3\u003eThe 35µm Slit: Balancing Resolution and Light Throughput\u003c\/h3\u003e\n\u003cp\u003eIn spectroscopy, the slit width directly controls the trade-off between the detail in your spectrum and its brightness. The 35 µm slit for the Alpy and UVEX spectrographs is a popular choice because it represents a highly effective compromise for many observing conditions and targets.\u003c\/p\u003e\n\u003cp\u003eThe polished, reflective surface surrounding the slit allows you to view the entire star field through your guiding camera. This ensures you can keep your target perfectly centered on the nearly invisible slit for long exposures, maximizing signal and preventing drift.\u003c\/p\u003e\n\u003c\/div\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-bg-light\"\u003e\n\u003cdiv class=\"DAV-section\"\u003e\n\u003ch3\u003eSlit Selection for Alpy \u0026amp; UVEX: The 35µm Slit vs. Other Options\u003c\/h3\u003e\n\u003cp\u003eChoosing the correct slit is fundamental to achieving your scientific goals. While the 35µm slit is an excellent all-rounder, understanding its context helps you make the right decision for your specific target.\u003c\/p\u003e\n\u003cul\u003e\n\u003cli\u003e\n\u003cstrong\u003evs. Narrower Slits (e.g., 25 µm):\u003c\/strong\u003e A narrower slit yields higher spectral resolution but passes significantly less light. It is the superior choice for studying fine absorption lines in the spectra of bright stars, where signal is plentiful.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003evs. Wider Slits (e.g., 50 µm+):\u003c\/strong\u003e A wider slit captures more photons, which is critical for obtaining a usable signal on very faint objects like distant galaxies or low-surface-brightness nebulae. The trade-off is a lower-resolution spectrum where fine details may be blurred.\u003c\/li\u003e\n\u003c\/ul\u003e\n\u003cp\u003eThe 35µm slit is the workhorse option, ideal for general stellar classification, analyzing emission lines in planetary nebulae, and capturing spectra of moderately bright comets and supernovae.\u003c\/p\u003e\n\u003c\/div\u003e\n\u003c\/div\u003e\n\u003c\/div\u003e\n\u003c\/li\u003e\n\u003cli\u003e\n\u003cdiv class=\"DAV-accordion\"\u003e\n\u003ch3 class=\"DAV-accordion-Q\"\u003eWhat is the main purpose of the Alpy \u0026amp; UVEX 35 µm slit?\u003c\/h3\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion-A\"\u003e\n\u003cp\u003eIt serves two critical functions. The precision-cut \u003cstrong\u003e35 µm slit\u003c\/strong\u003e acts as the entrance aperture for the spectrograph, determining the resolution of the spectrum. The reflective surface around the slit acts as a \u003cstrong\u003eguiding mirror\u003c\/strong\u003e, allowing you to see the star field and keep your target perfectly centered for the duration of an exposure.\u003c\/p\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion\"\u003e\n\u003ch3 class=\"DAV-accordion-Q\"\u003eHow does the 35 µm slit affect the spectral resolution of my Alpy or UVEX?\u003c\/h3\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion-A\"\u003e\n\u003cp\u003eThe slit width is a primary factor in determining spectral resolution. A narrower slit produces a sharper, higher-resolution spectrum, allowing you to resolve finer details. The \u003cstrong\u003e35 µm slit\u003c\/strong\u003e provides a strong intermediate resolution, suitable for many projects from stellar classification to emission line studies in nebulae.\u003c\/p\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion\"\u003e\n\u003ch3 class=\"DAV-accordion-Q\"\u003eWhen should I choose the 35 µm slit over a narrower one for my Alpy\/UVEX?\u003c\/h3\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion-A\"\u003e\n\u003cp\u003eYou should choose the \u003cstrong\u003e35 µm slit\u003c\/strong\u003e when light throughput is as important as resolution. While a narrower slit (e.g., 25µm) offers higher resolution, it passes less light, requiring longer exposures. The 35µm slit is ideal for moderately faint targets or when seeing conditions don't support the highest possible resolution.\u003c\/p\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion\"\u003e\n\u003ch3 class=\"DAV-accordion-Q\"\u003eCan I use the Alpy \u0026amp; UVEX 35 µm slit for guiding on my target star?\u003c\/h3\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion-A\"\u003e\n\u003cp\u003eYes, absolutely. The component is a guiding mirror with a slit at its center. The light from your target that doesn't pass through the slit is reflected into your guiding camera, allowing you to monitor the star's position and make precise tracking corrections.\u003c\/p\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion\"\u003e\n\u003ch3 class=\"DAV-accordion-Q\"\u003eIs the 35 µm slit a good choice for observing faint nebulae like the Orion Nebula (M42) with a Shelyak spectrograph?\u003c\/h3\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion-A\"\u003e\n\u003cp\u003eYes, the \u003cstrong\u003e35 µm slit\u003c\/strong\u003e is an excellent choice for targets like the Orion Nebula (M42). It allows enough light from the extended object to pass through to achieve a good signal-to-noise ratio in a reasonable time, while still providing enough resolution to separate key emission lines like Hydrogen-alpha and Oxygen-III.\u003c\/p\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion\"\u003e\n\u003ch3 class=\"DAV-accordion-Q\"\u003eFor measuring the redshift of a bright quasar like 3C 273, would the 35 µm slit be appropriate for my UVEX?\u003c\/h3\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion-A\"\u003e\n\u003cp\u003eThe \u003cstrong\u003e35 µm slit\u003c\/strong\u003e is a very capable option for a bright quasar like 3C 273. It provides a good balance, capturing enough light for a clear continuum while delivering the resolution needed to accurately measure the shift in prominent spectral lines, such as the broad Hydrogen-beta line used for redshift calculations.\u003c\/p\u003e\n\u003c\/div\u003e\n\u003c\/li\u003e\n\u003cli\u003e\n\u003ctable class=\"DAV-specifications\"\u003e\n\u003ctbody\u003e\n\u003ctr\u003e\n\u003ctd\u003eSlit Width\u003c\/td\u003e\n\u003ctd\u003e35 µm\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eCompatibility\u003c\/td\u003e\n\u003ctd\u003eShelyak Alpy and UVEX series spectrographs\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003c\/tbody\u003e\n\u003c\/table\u003e\n\u003c\/li\u003e\n\u003cli\u003e\n\u003cul class=\"DAV-grid\"\u003e\n\u003cli class=\"DAV-grid-item\"\u003e\n\u003cdiv\u003e\n\u003cp class=\"DAV-item-title\"\u003eAlpy \u0026amp; UVEX 35 µm slit\u003c\/p\u003e\n\u003cp class=\"DAV-item-subtitle\"\u003e× 1\u003c\/p\u003e\n\u003c\/div\u003e\n\u003c\/li\u003e\n\u003c\/ul\u003e\n\u003c\/li\u003e\n\u003cli\u003e\n\u003cul class=\"DAV-grid\"\u003e\n\u003cli class=\"DAV-grid-item\"\u003e\u003ca href=\"https:\/\/cdn.shopify.com\/s\/files\/1\/0753\/5280\/1565\/files\/Shelyak_Alpy_600_Manual.pdf\" target=\"_blank\"\u003e\u003csvg class=\"DAV-img-box\" viewbox=\"0 0 512 512\" xmlns=\"http:\/\/www.w3.org\/2000\/svg\"\u003e\u003cpath d=\"M0 64C0 28.7 28.7 0 64 0L224 0l0 128c0 17.7 14.3 32 32 32l128 0 0 144-208 0c-35.3 0-64 28.7-64 64l0 144-48 0c-35.3 0-64-28.7-64-64L0 64zm384 64l-128 0L256 0 384 128zM176 352l32 0c30.9 0 56 25.1 56 56s-25.1 56-56 56l-16 0 0 32c0 8.8-7.2 16-16 16s-16-7.2-16-16l0-48 0-80c0-8.8 7.2-16 16-16zm32 80c13.3 0 24-10.7 24-24s-10.7-24-24-24l-16 0 0 48 16 0zm96-80l32 0c26.5 0 48 21.5 48 48l0 64c0 26.5-21.5 48-48 48l-32 0c-8.8 0-16-7.2-16-16l0-128c0-8.8 7.2-16 16-16zm32 128c8.8 0 16-7.2 16-16l0-64c0-8.8-7.2-16-16-16l-16 0 0 96 16 0zm80-112c0-8.8 7.2-16 16-16l48 0c8.8 0 16 7.2 16 16s-7.2 16-16 16l-32 0 0 32 32 0c8.8 0 16 7.2 16 16s-7.2 16-16 16l-32 0 0 48c0 8.8-7.2 16-16 16s-16-7.2-16-16l0-64 0-64z\" fill=\"#0047a7\"\u003e\u003c\/path\u003e\u003c\/svg\u003e\n\u003cdiv\u003e\n\u003cp class=\"DAV-item-title\"\u003eShelyak Alpy 600 Manual\u003c\/p\u003e\n\u003c\/div\u003e\n\u003c\/a\u003e\u003c\/li\u003e\n\u003c\/ul\u003e\n\u003c\/li\u003e\n\u003cli\u003e\n\u003ca href=\"https:\/\/davidastro.com\/pages\/shelyak-warranty-policy\" rel=\"noopener\" target=\"_blank\"\u003eShelyak 1-Year Warranty\u003c\/a\u003e\n\u003c\/li\u003e\n\u003c\/ul\u003e","brand":"Shelyak","offers":[{"title":"Default Title","offer_id":52943049195805,"sku":"SHK-SE0150","price":305.0,"currency_code":"CAD","in_stock":true}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0753\/5280\/1565\/files\/Shelyak-Alpy-UVEX-35-m-slit-1_b2bb2b2b-316f-4f80-84b8-877210aaf9ff.jpg?v=1789616376"},{"product_id":"shelyak-se0192","title":"Shelyak Lhires III Slit Holder","description":"\u003cul class=\"DAV-feature-list\"\u003e\n\u003cli\u003eEnables rapid slit changes for the Lhires III spectroscope\u003c\/li\u003e\n\u003cli\u003eImproves observational efficiency in the field\u003c\/li\u003e\n\u003cli\u003eCompatible with standard, wide, and photometric slits\u003c\/li\u003e\n\u003cli\u003eSecurely holds slits for repeatable results\u003c\/li\u003e\n\u003c\/ul\u003e\n\u003c!-- more --\u003e\n\u003cul class=\"tabs\"\u003e\n\u003cli class=\"active\"\u003eDescription\u003c\/li\u003e\n\u003cli\u003eFAQ\u003c\/li\u003e\n\n\u003cli\u003eDownloads\u003c\/li\u003e\n\u003cli\u003eWarranty\u003c\/li\u003e\n\u003c\/ul\u003e\n\n\u003cul class=\"tabs-content\"\u003e\n\u003cli class=\"active\"\u003e\n\u003cdiv\u003e\n  \u003cdiv class=\"DAV-bg-light\"\u003e\n    \u003cdiv class=\"DAV-section-center\"\u003e\n      \u003ch2\u003eLhires III Slit Holder\u003c\/h2\u003e\n      \u003cp\u003eThe Shelyak Lhires III Slit Holder is an essential accessory designed to significantly streamline your spectroscopic workflow. It allows for the rapid exchange of different slits, enabling you to quickly adapt the Lhires III spectroscope for various observational targets and scientific goals. This holder is compatible with Shelyak's wide, photometric, and standard slits, providing critical operational flexibility during an observing session.\u003c\/p\u003e\n    \u003c\/div\u003e\n  \u003c\/div\u003e\n\n  \u003cdiv class=\"DAV-bg-light\"\u003e\n    \u003cdiv class=\"DAV-section\"\u003e\n      \u003ch3\u003eStreamline Slit Changes on the Lhires III\u003c\/h3\u003e\n      \u003cp\u003eFor observers using the Lhires III for multiple projects in a single night, changing slits can be a time-consuming process. The Lhires III Slit Holder eliminates this bottleneck by allowing you to swap between different slit types in seconds. This ensures you spend more time acquiring data and less time reconfiguring your instrument in the dark.\u003c\/p\u003e\n    \u003c\/div\u003e\n  \u003c\/div\u003e\n  \n  \u003cdiv class=\"DAV-bg-light\"\u003e\n    \u003cdiv class=\"DAV-section\"\u003e\n      \u003ch3\u003eAdapt to Multiple Spectroscopic Targets\u003c\/h3\u003e\n      \u003cp\u003eThis holder is the key to unlocking the full scientific potential of your Lhires III by providing a secure and repeatable mounting point for Shelyak's range of specialized slits.\u003c\/p\u003e\n      \u003cul\u003e\n        \u003cli\u003e\n\u003cstrong\u003eStandard Slits:\u003c\/strong\u003e Use for general-purpose, high-resolution stellar spectra of bright targets.\u003c\/li\u003e\n        \u003cli\u003e\n\u003cstrong\u003eWide Slits:\u003c\/strong\u003e Switch to these for capturing more light from faint objects like comets or nebulae, sacrificing some resolution for a stronger signal.\u003c\/li\u003e\n        \u003cli\u003e\n\u003cstrong\u003ePhotometric Slits:\u003c\/strong\u003e Install for precise brightness measurements, where capturing the total flux from a star is more critical than fine spectral detail.\u003c\/li\u003e\n      \u003c\/ul\u003e\n    \u003c\/div\u003e\n  \u003c\/div\u003e\n\n\u003c\/div\u003e\n\u003c\/li\u003e\n\n\u003cli\u003e\n  \u003cdiv class=\"DAV-accordion\"\u003e\n    \u003ch3 class=\"DAV-accordion-Q\"\u003eWhat is the main advantage of using the Lhires III Slit Holder?\u003c\/h3\u003e\n  \u003c\/div\u003e\n  \u003cdiv class=\"DAV-accordion-A\"\u003e\n    \u003cp\u003e\u003cstrong\u003eEfficiency.\u003c\/strong\u003e The primary benefit of the Lhires III Slit Holder is the ability to change slits very quickly without complex disassembly of the spectroscope. This saves valuable observing time and allows you to adapt your instrument to changing targets or conditions with minimal downtime.\u003c\/p\u003e\n  \u003c\/div\u003e\n  \u003cdiv class=\"DAV-accordion\"\u003e\n    \u003ch3 class=\"DAV-accordion-Q\"\u003eWhich slits are compatible with the Lhires III Slit Holder?\u003c\/h3\u003e\n  \u003c\/div\u003e\n  \u003cdiv class=\"DAV-accordion-A\"\u003e\n    \u003cp\u003eThe Lhires III Slit Holder is specifically designed to be used with the family of slits made by Shelyak for the Lhires III spectroscope. This includes their \u003cstrong\u003estandard, wide, and photometric slits\u003c\/strong\u003e.\u003c\/p\u003e\n  \u003c\/div\u003e\n  \u003cdiv class=\"DAV-accordion\"\u003e\n    \u003ch3 class=\"DAV-accordion-Q\"\u003eDo I need a separate Lhires III Slit Holder for each slit I own?\u003c\/h3\u003e\n  \u003c\/div\u003e\n  \u003cdiv class=\"DAV-accordion-A\"\u003e\n    \u003cp\u003eNo, a single holder is installed in the spectroscope, and you can insert your various slits into it. However, some advanced users purchase multiple holders and pre-install their most-used slits to make field swaps nearly instantaneous.\u003c\/p\u003e\n  \u003c\/div\u003e\n  \u003cdiv class=\"DAV-accordion\"\u003e\n    \u003ch3 class=\"DAV-accordion-Q\"\u003eIf I am studying a Be star like Gamma Cassiopeiae and then a faint comet, how does the Lhires III Slit Holder help?\u003c\/h3\u003e\n  \u003c\/div\u003e\n  \u003cdiv class=\"DAV-accordion-A\"\u003e\n    \u003cp\u003eThis is a perfect use case. You would use a narrow, standard slit for the high-resolution spectrum of the bright Be star. With the Lhires III Slit Holder, you can then quickly swap to a wide slit to maximize light collection from the faint, diffuse comet, all without a lengthy and difficult reconfiguration in the dark.\u003c\/p\u003e\n  \u003c\/div\u003e\n  \u003cdiv class=\"DAV-accordion\"\u003e\n    \u003ch3 class=\"DAV-accordion-Q\"\u003eI want to perform photometry on an eclipsing binary with my Lhires III. Which slit should I use with the holder?\u003c\/h3\u003e\n  \u003c\/div\u003e\n  \u003cdiv class=\"DAV-accordion-A\"\u003e\n    \u003cp\u003eFor photometry, you would use the dedicated \u003cstrong\u003ephotometric slit\u003c\/strong\u003e with your Lhires III Slit Holder. This type of slit is designed to ensure all the starlight enters the spectroscope, which is critical for accurate brightness measurements, even if it results in lower spectral resolution.\u003c\/p\u003e\n  \u003c\/div\u003e\n  \u003cdiv class=\"DAV-accordion\"\u003e\n    \u003ch3 class=\"DAV-accordion-Q\"\u003eIs installation of the Lhires III Slit Holder difficult?\u003c\/h3\u003e\n  \u003c\/div\u003e\n  \u003cdiv class=\"DAV-accordion-A\"\u003e\n    \u003cp\u003eThe holder is designed for straightforward integration into the Lhires III spectroscope body. For detailed instructions, please refer to the official Shelyak Lhires III user manual, which covers the replacement of the slit assembly.\u003c\/p\u003e\n  \u003c\/div\u003e\n\u003c\/li\u003e\n\n\u003cli\u003e\n\u003cul class=\"DAV-grid\"\u003e\n\u003cli class=\"DAV-grid-item\"\u003e\u003ca href=\"https:\/\/cdn.shopify.com\/s\/files\/1\/0753\/5280\/1565\/files\/Shelyak_Lhires_III_Manual.pdf\" target=\"_blank\"\u003e\u003csvg class=\"DAV-img-box\" viewbox=\"0 0 512 512\" xmlns=\"http:\/\/www.w3.org\/2000\/svg\"\u003e\u003cpath d=\"M0 64C0 28.7 28.7 0 64 0L224 0l0 128c0 17.7 14.3 32 32 32l128 0 0 144-208 0c-35.3 0-64 28.7-64 64l0 144-48 0c-35.3 0-64-28.7-64-64L0 64zm384 64l-128 0L256 0 384 128zM176 352l32 0c30.9 0 56 25.1 56 56s-25.1 56-56 56l-16 0 0 32c0 8.8-7.2 16-16 16s-16-7.2-16-16l0-48 0-80c0-8.8 7.2-16 16-16zm32 80c13.3 0 24-10.7 24-24s-10.7-24-24-24l-16 0 0 48 16 0zm96-80l32 0c26.5 0 48 21.5 48 48l0 64c0 26.5-21.5 48-48 48l-32 0c-8.8 0-16-7.2-16-16l0-128c0-8.8 7.2-16 16-16zm32 128c8.8 0 16-7.2 16-16l0-64c0-8.8-7.2-16-16-16l-16 0 0 96 16 0zm80-112c0-8.8 7.2-16 16-16l48 0c8.8 0 16 7.2 16 16s-7.2 16-16 16l-32 0 0 32 32 0c8.8 0 16 7.2 16 16s-7.2 16-16 16l-32 0 0 48c0 8.8-7.2 16-16 16s-16-7.2-16-16l0-64 0-64z\" fill=\"#0047a7\"\u003e\u003c\/path\u003e\u003c\/svg\u003e\n\u003cdiv\u003e\n\u003cp class=\"DAV-item-title\"\u003eShelyak Lhires III Manual\u003c\/p\u003e\n\u003c\/div\u003e\n\u003c\/a\u003e\u003c\/li\u003e\n\u003c\/ul\u003e\n\u003c\/li\u003e\n\n\u003cli\u003e\n\u003ca href=\"https:\/\/davidastro.com\/pages\/shelyak-warranty-policy\" rel=\"noopener\" target=\"_blank\"\u003eShelyak 1-Year Warranty\u003c\/a\u003e\n\u003c\/li\u003e\n\u003c\/ul\u003e","brand":"Shelyak","offers":[{"title":"Default Title","offer_id":52943050440989,"sku":"SHK-SE0192","price":197.0,"currency_code":"CAD","in_stock":true}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0753\/5280\/1565\/files\/Shelyak-Lhires-III-slit-holder-1_8610993a-8ede-4c31-b8ed-4de9a5be8e5e.jpg?v=1789616417"},{"product_id":"shelyak-se0193","title":"Shelyak LISA Slit Holder","description":"\u003cul class=\"DAV-feature-list\"\u003e\n\u003cli\u003eEnables rapid interchange of spectroscopic slits\u003c\/li\u003e\n\u003cli\u003eDesigned specifically for the Shelyak LISA Spectroscope\u003c\/li\u003e\n\u003cli\u003eCompatible with standard, wide, and photometric slits\u003c\/li\u003e\n\u003cli\u003eStreamlines workflow for varied astronomical targets\u003c\/li\u003e\n\u003c\/ul\u003e\n\u003c!-- more --\u003e\n\u003cul class=\"tabs\"\u003e\n\u003cli class=\"active\"\u003eDescription\u003c\/li\u003e\n\u003cli\u003eFAQ\u003c\/li\u003e\n\u003cli\u003eWarranty\u003c\/li\u003e\n\u003c\/ul\u003e\n\n\u003cul class=\"tabs-content\"\u003e\n\u003cli class=\"active\"\u003e\n\u003cdiv\u003e\n  \u003cdiv class=\"DAV-bg-light\"\u003e\n    \u003cdiv class=\"DAV-section-center\"\u003e\n      \u003ch2\u003eLISA Slit Holder\u003c\/h2\u003e\n      \u003cp\u003eThe Shelyak LISA Slit Holder is the essential accessory for adding operational flexibility to your LISA spectroscope. It provides the core mechanism for rapidly and easily swapping between different slits, allowing you to adapt your instrument's configuration in the field to match the scientific requirements of any target, from faint nebulae to bright variable stars.\u003c\/p\u003e\n    \u003c\/div\u003e\n  \u003c\/div\u003e\n\n  \u003cdiv class=\"DAV-bg-light\"\u003e\n    \u003cdiv class=\"DAV-section\"\u003e\n      \u003ch3\u003eInterchangeable Slit System for the LISA Spectroscope\u003c\/h3\u003e\n      \u003cp\u003eThis holder transforms the LISA from a single-slit instrument into a modular system. Instead of being locked into one slit width for an entire night, you can pre-load multiple slits into individual holders and exchange them in moments. This capability is critical for observers who need to switch between different types of spectroscopy during a single session.\u003c\/p\u003e\n    \u003c\/div\u003e\n  \u003c\/div\u003e\n\n  \u003cdiv class=\"DAV-bg-light\"\u003e\n    \u003cdiv class=\"DAV-section\"\u003e\n      \u003ch3\u003eAdapt Your LISA for Different Scientific Targets\u003c\/h3\u003e\n      \u003cp\u003eThe LISA Slit Holder is designed to accept a range of Shelyak slits, each optimized for a specific astronomical application. By using this holder, you can seamlessly switch between different observational modes.\u003c\/p\u003e\n      \u003cul\u003e\n        \u003cli\u003e\n\u003cstrong\u003eStandard Slits:\u003c\/strong\u003e Use for general-purpose, high-resolution spectroscopy of stars and other point sources.\u003c\/li\u003e\n        \u003cli\u003e\n\u003cstrong\u003eWide Slits:\u003c\/strong\u003e Ideal for capturing the spectra of faint, extended objects like galaxies or nebulae where maximizing light throughput is more important than resolution.\u003c\/li\u003e\n        \u003cli\u003e\n\u003cstrong\u003ePhotometric Slits:\u003c\/strong\u003e Designed for spectrophotometry, allowing for accurate measurements of an object's flux, which is crucial for studying variable stars or supernovae.\u003c\/li\u003e\n      \u003c\/ul\u003e\n    \u003c\/div\u003e\n  \u003c\/div\u003e\n\n\u003c\/div\u003e\n\u003c\/li\u003e\n\n\u003cli\u003e\n  \u003cdiv class=\"DAV-accordion\"\u003e\n    \u003ch3 class=\"DAV-accordion-Q\"\u003eWhat is the purpose of the LISA Slit Holder?\u003c\/h3\u003e\n  \u003c\/div\u003e\n  \u003cdiv class=\"DAV-accordion-A\"\u003e\n    \u003cp\u003eThe LISA Slit Holder is designed specifically for the Shelyak LISA spectroscope to make changing slits fast and simple. This allows an observer to use multiple slit types (e.g., standard, wide, photometric) during a single observing session without complex disassembly, adapting the instrument to different targets and scientific goals.\u003c\/p\u003e\n  \u003c\/div\u003e\n  \u003cdiv class=\"DAV-accordion\"\u003e\n    \u003ch3 class=\"DAV-accordion-Q\"\u003eDoes the LISA Slit Holder include any slits?\u003c\/h3\u003e\n  \u003c\/div\u003e\n  \u003cdiv class=\"DAV-accordion-A\"\u003e\n    \u003cp\u003eNo, this product is only the holder itself. The various slits (standard, wide, photometric) must be purchased separately. This allows you to build a custom kit with only the slit types you need for your specific research or observing program.\u003c\/p\u003e\n  \u003c\/div\u003e\n  \u003cdiv class=\"DAV-accordion\"\u003e\n    \u003ch3 class=\"DAV-accordion-Q\"\u003eWhat types of slits can I use with the LISA Slit Holder?\u003c\/h3\u003e\n  \u003c\/div\u003e\n  \u003cdiv class=\"DAV-accordion-A\"\u003e\n    \u003cp\u003eThe holder is compatible with Shelyak's dedicated slits for the LISA spectroscope, which include standard slits for high-resolution work, wide slits for faint objects, and photometric slits for flux analysis.\u003c\/p\u003e\n  \u003c\/div\u003e\n  \u003cdiv class=\"DAV-accordion\"\u003e\n    \u003ch3 class=\"DAV-accordion-Q\"\u003eWhy would I need to change slits on my LISA spectroscope during an observing session?\u003c\/h3\u003e\n  \u003c\/div\u003e\n  \u003cdiv class=\"DAV-accordion-A\"\u003e\n    \u003cp\u003eDifferent astronomical targets require different slit widths for optimal results. You might start a session by capturing a high-resolution spectrum of a bright star with a narrow slit, then switch to a wide slit to capture more light from a faint galaxy. The holder makes this transition efficient.\u003c\/p\u003e\n  \u003c\/div\u003e\n    \u003cdiv class=\"DAV-accordion\"\u003e\n    \u003ch3 class=\"DAV-accordion-Q\"\u003eHow does using a wide slit with the LISA Slit Holder affect my spectra of a faint galaxy like the Whirlpool Galaxy (M51)?\u003c\/h3\u003e\n  \u003c\/div\u003e\n  \u003cdiv class=\"DAV-accordion-A\"\u003e\n    \u003cp\u003eFor a faint, extended object like M51, a wide slit allows more photons from the galaxy's core or spiral arms to enter the spectroscope. This increases the signal-to-noise ratio, making it possible to detect faint emission or absorption features that would be lost with a narrow slit, though it does so at the cost of lower spectral resolution.\u003c\/p\u003e\n  \u003c\/div\u003e\n    \u003cdiv class=\"DAV-accordion\"\u003e\n    \u003ch3 class=\"DAV-accordion-Q\"\u003eIf I want to measure the flux of a variable star like Betelgeuse with my LISA, which slit should I use in the holder?\u003c\/h3\u003e\n  \u003c\/div\u003e\n  \u003cdiv class=\"DAV-accordion-A\"\u003e\n    \u003cp\u003eFor measuring accurate brightness (flux), you should use a \u003cstrong\u003ephotometric slit\u003c\/strong\u003e in your LISA Slit Holder. These slits are designed to be wide enough to ensure all the light from the star enters the spectroscope, even with minor tracking errors or poor seeing, which is essential for reliable spectrophotometry.\u003c\/p\u003e\n  \u003c\/div\u003e\n\u003c\/li\u003e\n\n\u003cli\u003e\n\u003ca href=\"https:\/\/davidastro.com\/pages\/shelyak-warranty-policy\" rel=\"noopener\" target=\"_blank\"\u003eShelyak 1-Year Warranty\u003c\/a\u003e\n\u003c\/li\u003e\n\u003c\/ul\u003e","brand":"Shelyak","offers":[{"title":"Default Title","offer_id":52943050834205,"sku":"SHK-SE0193","price":197.0,"currency_code":"CAD","in_stock":true}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0753\/5280\/1565\/files\/Shelyak-LISA-slit-holder-1_ce663029-18d0-44db-9ebd-e4a8a70b33cf.jpg?v=1789616426"},{"product_id":"shelyak-se0194","title":"Shelyak LISA \u0026 Lhires III Photometric Slit","description":"\u003cul class=\"DAV-feature-list\"\u003e\n\u003cli\u003eEnables true spectrophotometry with LISA \u0026amp; Lhires III spectrographs\u003c\/li\u003e\n\u003cli\u003eDual-width design for simultaneous high-resolution spectra and total flux measurement\u003c\/li\u003e\n\u003cli\u003eCaptures all starlight for precise photometric data\u003c\/li\u003e\n\u003cli\u003eIdeal for studying variable stars, novae, and supernovae\u003c\/li\u003e\n\u003cli\u003eDirect-fit accessory for specified Shelyak instruments\u003c\/li\u003e\n\u003c\/ul\u003e\n\u003c!-- more --\u003e\n\u003cul class=\"tabs\"\u003e\n\u003cli class=\"active\"\u003eDescription\u003c\/li\u003e\n\u003cli\u003eFAQ\u003c\/li\u003e\n\u003cli\u003eWarranty\u003c\/li\u003e\n\u003c\/ul\u003e\n\u003cul class=\"tabs-content\"\u003e\n\u003cli class=\"active\"\u003e\n\u003cdiv\u003e\n\u003cdiv class=\"DAV-bg-light\"\u003e\n\u003cdiv class=\"DAV-section-center\"\u003e\n\u003ch2\u003eLISA \u0026amp; Lhires III Photometric Slit\u003c\/h2\u003e\n\u003cp\u003eThis Photometric Slit set for the Shelyak LISA and Lhires III spectrographs enables true scientific spectrophotometry by combining high-resolution spectral analysis with precise brightness measurement. Each slit features a unique dual-width design, with a narrow section to maintain the full resolving power of your instrument and a wide section to ensure every photon from your target star is collected. This allows you to create fully flux-calibrated spectra, essential for analyzing variable stars, novae, and other transient astronomical events.\u003c\/p\u003e\n\u003c\/div\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-bg-light\"\u003e\n\u003cdiv class=\"DAV-section\"\u003e\n\u003ch3\u003eDual-Width Slit Design: The Key to Accurate Spectrophotometry\u003c\/h3\u003e\n\u003cp\u003eStandard spectroscopic slits are a compromise; narrow for high resolution, but at the risk of losing starlight due to atmospheric seeing, which corrupts brightness data. This photometric slit solves that problem by providing two slit widths in one. You can acquire a high-resolution spectrum using the narrow portion and a separate, photometrically accurate reading through the wide portion.\u003c\/p\u003e\n\u003cp\u003eBy combining observations from both sections, you can normalize the high-resolution spectrum to the total, accurate brightness of the star. This unlocks the ability to measure not just the composition and velocity of an object, but its absolute energy output across the spectrum—the core purpose of spectrophotometry.\u003c\/p\u003e\n\u003c\/div\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-bg-light\"\u003e\n\u003cdiv class=\"DAV-section\"\u003e\n\u003ch3\u003eCompatibility and Use Case: For Shelyak LISA \u0026amp; Lhires III Spectrographs\u003c\/h3\u003e\n\u003cp\u003eThis set of slits is designed specifically as an accessory for the Shelyak LISA and Lhires III spectrographs. It replaces the standard slit, allowing observers to upgrade their instrument's capability from pure spectroscopy to quantitative spectrophotometry.\u003c\/p\u003e\n\u003cp\u003eThe primary application is for any research where both the spectral features and the absolute brightness of an object are changing. This is critical for characterizing the physics of cataclysmic variable stars, tracking the light curve and spectral evolution of a supernova, or monitoring the activity of young stellar objects.\u003c\/p\u003e\n\u003c\/div\u003e\n\u003c\/div\u003e\n\u003c\/div\u003e\n\u003c\/li\u003e\n\u003cli\u003e\n\u003cdiv class=\"DAV-accordion\"\u003e\n\u003ch3 class=\"DAV-accordion-Q\"\u003eWhat is the purpose of the LISA \u0026amp; Lhires III Photometric Slit?\u003c\/h3\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion-A\"\u003e\n\u003cp\u003eThe Photometric Slit allows you to perform \u003cstrong\u003espectrophotometry\u003c\/strong\u003e, which is the measurement of a star's spectrum (its light broken down by color) combined with an accurate measurement of its total brightness (photometry). This is crucial for creating scientifically accurate, flux-calibrated stellar spectra.\u003c\/p\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion\"\u003e\n\u003ch3 class=\"DAV-accordion-Q\"\u003eHow does the dual-width design of the Photometric Slit work?\u003c\/h3\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion-A\"\u003e\n\u003cp\u003eEach slit has two sections:\u003c\/p\u003e\n\u003cul\u003e\n\u003cli\u003eA \u003cstrong\u003enarrow part\u003c\/strong\u003e that provides the high spectral resolution needed to see fine details in a star's spectrum.\u003c\/li\u003e\n\u003cli\u003eA \u003cstrong\u003ewide part\u003c\/strong\u003e that ensures all the light from the star enters the spectrograph, even with poor seeing. This is essential for getting an accurate brightness measurement.\u003c\/li\u003e\n\u003c\/ul\u003e\n\u003cp\u003eBy taking observations with both parts of the slit, you can combine the detailed spectrum from the narrow part with the accurate brightness data from the wide part.\u003c\/p\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion\"\u003e\n\u003ch3 class=\"DAV-accordion-Q\"\u003eIs the Photometric Slit compatible with spectrographs other than the Shelyak LISA and Lhires III?\u003c\/h3\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion-A\"\u003e\n\u003cp\u003eNo, this accessory is specifically designed for use with the Shelyak Instruments \u003cstrong\u003eLISA\u003c\/strong\u003e and \u003cstrong\u003eLhires III\u003c\/strong\u003e spectrographs. It is not intended for use with other models or brands.\u003c\/p\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion\"\u003e\n\u003ch3 class=\"DAV-accordion-Q\"\u003eWhy can't I just use a single wide slit for both spectroscopy and photometry?\u003c\/h3\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion-A\"\u003e\n\u003cp\u003eWhile a wide slit captures all the star's light for good photometry, it dramatically reduces the spectrograph's resolution. Spectral lines would appear blurry and smeared, and fine details would be lost. The dual-width design allows you to get the best of both worlds: high resolution and accurate photometry, by taking separate, specialized exposures.\u003c\/p\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion\"\u003e\n\u003ch3 class=\"DAV-accordion-Q\"\u003eHow would I use the Photometric Slit to study a variable star like Algol (Beta Persei)?\u003c\/h3\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion-A\"\u003e\n\u003cp\u003eTo study an eclipsing binary like Algol (Beta Persei), you would take a series of exposures over time. For each observation, you would capture one spectrum with the narrow part of the slit to record any changes in the spectral lines (like doppler shifts), and another with the wide part to precisely measure the drop in brightness during the eclipse. This provides a complete picture of the system's dynamics.\u003c\/p\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion\"\u003e\n\u003ch3 class=\"DAV-accordion-Q\"\u003eIf I'm observing a supernova in a galaxy like the Whirlpool Galaxy (M51), what advantage does this slit give me?\u003c\/h3\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion-A\"\u003e\n\u003cp\u003eFor a supernova in M51, the Photometric Slit is invaluable. You would use the narrow slit to capture high-resolution spectra of the expanding debris, identifying elements and measuring their velocities. You would then use the wide slit to accurately measure the supernova's changing brightness, creating a light curve. Combining these allows you to calculate the total energy output and model the physics of the explosion far more accurately than with a standard slit.\u003c\/p\u003e\n\u003c\/div\u003e\n\u003c\/li\u003e\n\n\u003cli\u003e\u003ca href=\"https:\/\/davidastro.com\/pages\/shelyak-warranty-policy\" rel=\"noopener\" target=\"_blank\"\u003eShelyak 1-Year Warranty\u003c\/a\u003e\u003c\/li\u003e\n\u003c\/ul\u003e","brand":"Shelyak","offers":[{"title":"Default Title","offer_id":52943051063581,"sku":"SHK-SE0194","price":305.0,"currency_code":"CAD","in_stock":true}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0753\/5280\/1565\/files\/Shelyak-LISA-Lhires-III-Photometric-Slit-1_96e40eb5-63be-4000-a492-6d82fc431e67.jpg?v=1789616434"},{"product_id":"shelyak-se0242","title":"Shelyak Grating module for the UVEX - 150 l\/mm","description":"\u003cul class=\"DAV-feature-list\"\u003e\n\u003cli\u003e150 lines\/mm Grating Density\u003c\/li\u003e\n\u003cli\u003eDesigned for the Shelyak UVEX Spectroscope\u003c\/li\u003e\n\u003cli\u003eOptimized for Low-Resolution, Wide-Coverage Spectroscopy\u003c\/li\u003e\n\u003cli\u003eInterchangeable Module for UVEX System\u003c\/li\u003e\n\u003c\/ul\u003e\n\u003c!-- more --\u003e\n\u003cul class=\"tabs\"\u003e\n\u003cli class=\"active\"\u003eDescription\u003c\/li\u003e\n\u003cli\u003eFAQ\u003c\/li\u003e\n\u003cli\u003eSpecifications\u003c\/li\u003e\n\u003cli\u003eIn the Box\u003c\/li\u003e\n\u003cli\u003eDownloads\u003c\/li\u003e\n\u003cli\u003eWarranty\u003c\/li\u003e\n\u003c\/ul\u003e\n\u003cul class=\"tabs-content\"\u003e\n\u003cli class=\"active\"\u003e\n\u003cdiv\u003e\n\u003cdiv class=\"DAV-bg-light\"\u003e\n\u003cdiv class=\"DAV-section-center\"\u003e\n\u003ch2\u003eGrating module for the UVEX - 150 l\/mm\u003c\/h2\u003e\n\u003cp\u003eThis optional 150 lines\/mm grating module expands the capabilities of your UVEX spectroscope, sitting at the lowest-resolution end of a lineup that includes 300, 600, 1200, and 1800 l\/mm options. By trading the high resolution of the standard 600 l\/mm grating for maximum wavelength coverage, the 150 l\/mm module is purpose-built for survey work and classifying a wide range of celestial objects in a single exposure.\u003c\/p\u003e\n\u003c\/div\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-bg-light\"\u003e\n\u003cdiv class=\"DAV-section\"\u003e\n\u003ch3\u003e150 l\/mm Grating: Maximizing Spectral Range for Survey Work\u003c\/h3\u003e\n\u003cp\u003eThe primary role of the 150 l\/mm grating is to capture the widest possible spectral range that your camera sensor can accommodate in a single frame. This low-dispersion capability is essential for survey projects where the goal is to quickly characterize many targets, such as classifying stars, identifying supernova types, or monitoring cometary emissions.\u003c\/p\u003e\n\u003cp\u003eFor faint targets, lower dispersion concentrates the object's light over fewer pixels, increasing the signal-to-noise ratio of the continuum. This makes the 150 l\/mm grating the most efficient choice for obtaining usable spectra of faint novae, asteroids, or distant quasars where capturing the overall spectral shape is more critical than resolving fine details.\u003c\/p\u003e\n\u003c\/div\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-bg-light\"\u003e\n\u003cdiv class=\"DAV-section\"\u003e\n\u003ch3\u003eUVEX 150 l\/mm vs. 600 l\/mm Grating: Resolution vs. Wavelength Coverage\u003c\/h3\u003e\n\u003cp\u003eChoosing between the optional 150 l\/mm grating and the standard 600 l\/mm grating is a direct trade-off between spectral detail and wavelength coverage. Your scientific objective determines which is the correct tool for the job.\u003c\/p\u003e\n\u003cul\u003e\n\u003cli\u003e\n\u003cstrong\u003eStandard 600 l\/mm Grating:\u003c\/strong\u003e This grating provides four times the resolution, making it the superior choice for resolving fine spectral features. It is ideal for measuring subtle Doppler shifts, studying complex stellar atmospheres, or separating closely spaced emission lines in planetary nebulae.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eOptional 150 l\/mm Grating:\u003c\/strong\u003e This grating captures a much wider band of the spectrum on the same sensor. This allows you to see the entire visible spectrum of an object at once, from the violet H-delta line to the red H-alpha line, without creating a mosaic of multiple images. This is invaluable for transient events or initial object classification.\u003c\/li\u003e\n\u003c\/ul\u003e\n\u003c\/div\u003e\n\u003c\/div\u003e\n\u003c\/div\u003e\n\u003c\/li\u003e\n\u003cli\u003e\n\u003cdiv class=\"DAV-accordion\"\u003e\n\u003ch3 class=\"DAV-accordion-Q\"\u003eWhy would I choose the 150 l\/mm grating for my UVEX instead of the standard 600 l\/mm?\u003c\/h3\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion-A\"\u003e\n\u003cp\u003eYou should choose the \u003cstrong\u003e150 l\/mm grating\u003c\/strong\u003e when your primary goal is to capture the widest possible range of wavelengths in a single exposure. It is ideal for survey work, classifying unknown objects, or studying targets with very broad spectral features. The standard \u003cstrong\u003e600 l\/mm grating\u003c\/strong\u003e is better when you need high resolution to study fine details within a narrow spectral window.\u003c\/p\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion\"\u003e\n\u003ch3 class=\"DAV-accordion-Q\"\u003eWhat kind of objects, like a Type Ia supernova or a Wolf-Rayet star, are best studied with the UVEX 150 l\/mm grating?\u003c\/h3\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion-A\"\u003e\n\u003cp\u003eThe UVEX 150 l\/mm grating is excellent for both. \u003cstrong\u003eType Ia supernovae\u003c\/strong\u003e are identified by a characteristic broad silicon absorption feature (Si II) at 6150Å, which is easily captured with this grating's wide coverage. \u003cstrong\u003eWolf-Rayet stars\u003c\/strong\u003e have extremely broad emission lines (sometimes hundreds of angstroms wide) from stellar winds, and the 150 l\/mm grating ensures the entire profile of these features fits within a single frame.\u003c\/p\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion\"\u003e\n\u003ch3 class=\"DAV-accordion-Q\"\u003eDoes the 150 l\/mm grating affect exposure times with the UVEX?\u003c\/h3\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion-A\"\u003e\n\u003cp\u003eYes. Because the 150 l\/mm grating disperses light less than a higher-density grating, it concentrates the starlight onto fewer pixels on your camera sensor. This results in a higher signal-to-noise ratio for the stellar continuum in a given exposure time, making it more efficient for capturing spectra of faint objects.\u003c\/p\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion-Q\"\u003eCan I use the UVEX 150 l\/mm grating to measure precise radial velocities?\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion-A\"\u003e\n\u003cp\u003eNo, this is not the right tool for that task. The low resolution of the 150 l\/mm grating is insufficient for measuring the small Doppler shifts required for precise radial velocity work. For those applications, a higher resolution grating, such as the standard 600 l\/mm or the optional 1200 l\/mm, is necessary.\u003c\/p\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion\"\u003e\n\u003ch3 class=\"DAV-accordion-Q\"\u003eIf I'm trying to classify a newly discovered comet with my UVEX, is the 150 l\/mm or the 600 l\/mm grating a better choice?\u003c\/h3\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion-A\"\u003e\n\u003cp\u003eThe \u003cstrong\u003e150 l\/mm grating\u003c\/strong\u003e is the better choice for initial comet classification. Cometary spectra often show broad emission bands from molecules like C2 (the Swan bands) and CN spread across the visible spectrum. The wide coverage of the 150 l\/mm grating allows you to capture all these features simultaneously to quickly assess the comet's composition.\u003c\/p\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion\"\u003e\n\u003ch3 class=\"DAV-accordion-Q\"\u003eIs it difficult to swap gratings on the Shelyak UVEX?\u003c\/h3\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion-A\"\u003e\n\u003cp\u003eNo, the Shelyak UVEX is designed as a modular system. Swapping gratings is a straightforward process, allowing you to reconfigure the spectroscope in the field to match your observing target and scientific goals for the night. Always refer to the UVEX manual for the correct procedure.\u003c\/p\u003e\n\u003c\/div\u003e\n\u003c\/li\u003e\n\u003cli\u003e\n\u003ctable class=\"DAV-specifications\"\u003e\n\u003ctbody\u003e\n\u003ctr\u003e\n\u003ctd\u003eGrating Density\u003c\/td\u003e\n\u003ctd\u003e150 lines\/mm\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eCompatibility\u003c\/td\u003e\n\u003ctd\u003eShelyak UVEX Spectroscope\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003c\/tbody\u003e\n\u003c\/table\u003e\n\u003c\/li\u003e\n\u003cli\u003e\n\u003cul class=\"DAV-grid\"\u003e\n\u003cli class=\"DAV-grid-item\"\u003e\n\u003cdiv\u003e\n\u003cp class=\"DAV-item-title\"\u003eUVEX 150 l\/mm Grating Module\u003c\/p\u003e\n\u003cp class=\"DAV-item-subtitle\"\u003e× 1\u003c\/p\u003e\n\u003c\/div\u003e\n\u003c\/li\u003e\n\u003c\/ul\u003e\n\u003c\/li\u003e\n\u003cli\u003e\n\u003cul class=\"DAV-grid\"\u003e\n\u003cli class=\"DAV-grid-item\"\u003e\u003ca href=\"https:\/\/cdn.shopify.com\/s\/files\/1\/0753\/5280\/1565\/files\/Shelyak_UVEX_Manual.pdf\" target=\"_blank\"\u003e\u003csvg class=\"DAV-img-box\" viewbox=\"0 0 512 512\" xmlns=\"http:\/\/www.w3.org\/2000\/svg\"\u003e\u003cpath d=\"M0 64C0 28.7 28.7 0 64 0L224 0l0 128c0 17.7 14.3 32 32 32l128 0 0 144-208 0c-35.3 0-64 28.7-64 64l0 144-48 0c-35.3 0-64-28.7-64-64L0 64zm384 64l-128 0L256 0 384 128zM176 352l32 0c30.9 0 56 25.1 56 56s-25.1 56-56 56l-16 0 0 32c0 8.8-7.2 16-16 16s-16-7.2-16-16l0-48 0-80c0-8.8 7.2-16 16-16zm32 80c13.3 0 24-10.7 24-24s-10.7-24-24-24l-16 0 0 48 16 0zm96-80l32 0c26.5 0 48 21.5 48 48l0 64c0 26.5-21.5 48-48 48l-32 0c-8.8 0-16-7.2-16-16l0-128c0-8.8 7.2-16 16-16zm32 128c8.8 0 16-7.2 16-16l0-64c0-8.8-7.2-16-16-16l-16 0 0 96 16 0zm80-112c0-8.8 7.2-16 16-16l48 0c8.8 0 16 7.2 16 16s-7.2 16-16 16l-32 0 0 32 32 0c8.8 0 16 7.2 16 16s-7.2 16-16 16l-32 0 0 48c0 8.8-7.2 16-16 16s-16-7.2-16-16l0-64 0-64z\" fill=\"#0047a7\"\u003e\u003c\/path\u003e\u003c\/svg\u003e\n\u003cdiv\u003e\n\u003cp class=\"DAV-item-title\"\u003eShelyak UVEX Manual\u003c\/p\u003e\n\u003c\/div\u003e\n\u003c\/a\u003e\u003c\/li\u003e\n\u003c\/ul\u003e\n\u003c\/li\u003e\n\u003cli\u003e\n\u003ca href=\"https:\/\/davidastro.com\/pages\/shelyak-warranty-policy\" rel=\"noopener\" target=\"_blank\"\u003eShelyak 1-Year Warranty\u003c\/a\u003e\n\u003c\/li\u003e\n\u003c\/ul\u003e","brand":"Shelyak","offers":[{"title":"Default Title","offer_id":52943051948317,"sku":"SHK-SE0242","price":992.0,"currency_code":"CAD","in_stock":true}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0753\/5280\/1565\/files\/Shelyak-Grating-module-for-the-UVEX-150-l-mm-1_8c7669aa-09e4-416e-a28d-be125b6cbaa3.jpg?v=1789616459"},{"product_id":"shelyak-se0243","title":"Shelyak Grating module for the UVEX - 300 l\/mm","description":"\u003cul class=\"DAV-feature-list\"\u003e\n\u003cli\u003e300 lines\/mm Grating Density\u003c\/li\u003e\n\u003cli\u003eOptional Interchangeable Module\u003c\/li\u003e\n\u003cli\u003eDesigned for the Shelyak UVEX Spectroscope\u003c\/li\u003e\n\u003cli\u003eLower Resolution, Wider Spectral Coverage\u003c\/li\u003e\n\u003c\/ul\u003e\n\u003c!-- more --\u003e\n\u003cul class=\"tabs\"\u003e\n\u003cli class=\"active\"\u003eDescription\u003c\/li\u003e\n\u003cli\u003eFAQ\u003c\/li\u003e\n\u003cli\u003eSpecifications\u003c\/li\u003e\n\u003cli\u003eIn the Box\u003c\/li\u003e\n\u003cli\u003eDownloads\u003c\/li\u003e\n\u003cli\u003eWarranty\u003c\/li\u003e\n\u003c\/ul\u003e\n\u003cul class=\"tabs-content\"\u003e\n\u003cli class=\"active\"\u003e\n\u003cdiv\u003e\n\u003cdiv class=\"DAV-bg-light\"\u003e\n\u003cdiv class=\"DAV-section-center\"\u003e\n\u003ch2\u003eGrating module for the UVEX - 300 l\/mm\u003c\/h2\u003e\n\u003cp\u003eThis optional Grating Module for the Shelyak UVEX spectroscope features a line density of 300 lines\/mm, offering a different balance of resolution and spectral coverage compared to the standard 600 l\/mm grating. It is a key component in a modular system that includes gratings from 150 l\/mm up to 1800 l\/mm, allowing you to tailor the instrument's capabilities to specific scientific targets.\u003c\/p\u003e\n\u003c\/div\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-bg-light\"\u003e\n\u003cdiv class=\"DAV-section\"\u003e\n\u003ch3\u003eThe 300 l\/mm Grating: Balancing Resolution and Spectral Range\u003c\/h3\u003e\n\u003cp\u003eIn spectroscopy, grating choice dictates a fundamental trade-off. The 300 lines\/mm grating disperses incoming light less aggressively than higher-density gratings. This results in lower spectral resolution but allows a significantly wider range of wavelengths to fit onto your camera's sensor in a single exposure.\u003c\/p\u003e\n\u003cp\u003eThis capability is critical for survey work, initial classification of variable stars or supernovae, and studying objects with very broad spectral features. For faint targets, concentrating the light over a smaller sensor area can also improve the signal-to-noise ratio for the overall spectrum, making it a valuable tool for capturing data on challenging objects.\u003c\/p\u003e\n\u003c\/div\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-bg-light\"\u003e\n\u003cdiv class=\"DAV-section\"\u003e\n\u003ch3\u003eChoosing Your Grating: 300 l\/mm vs. the 600 l\/mm Standard\u003c\/h3\u003e\n\u003cp\u003eWhile the UVEX's standard 600 l\/mm grating provides an excellent general-purpose balance for many projects, the 300 l\/mm module serves a specific and complementary role. You would choose the 300 l\/mm grating when your scientific goal prioritizes wavelength coverage over fine detail.\u003c\/p\u003e\n\u003cul\u003e\n\u003cli\u003e\n\u003cstrong\u003e300 l\/mm Grating:\u003c\/strong\u003e Best for wide-field spectroscopy. Use it to capture the full spectrum of a nova from the hydrogen-alpha to hydrogen-beta lines in one frame, or for classifying multiple stars in a cluster simultaneously.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003e600 l\/mm Grating (Standard):\u003c\/strong\u003e The versatile workhorse. Ideal for resolving the double-peaked emission lines in Be stars or studying the detailed structure of planetary nebulae spectra.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eHigher Density Gratings (1200\/1800 l\/mm):\u003c\/strong\u003e These are reserved for high-resolution studies of single, narrow spectral lines, such as measuring the radial velocity of a star via Doppler shift.\u003c\/li\u003e\n\u003c\/ul\u003e\n\u003c\/div\u003e\n\u003c\/div\u003e\n\u003c\/div\u003e\n\u003c\/li\u003e\n\u003cli\u003e\n\u003cdiv class=\"DAV-accordion\"\u003e\n\u003ch3 class=\"DAV-accordion-Q\"\u003eWhat is the primary use for the Shelyak UVEX 300 l\/mm grating?\u003c\/h3\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion-A\"\u003e\n\u003cp\u003eThe 300 l\/mm grating is designed for low-resolution spectroscopy where capturing a wide range of wavelengths in a single image is more important than resolving fine details. It is ideal for survey projects, classifying unknown objects, and studying targets with broad spectral features like supernovae or novae.\u003c\/p\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion\"\u003e\n\u003ch3 class=\"DAV-accordion-Q\"\u003eHow does the 300 l\/mm grating compare to the standard 600 l\/mm grating included with the UVEX?\u003c\/h3\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion-A\"\u003e\n\u003cp\u003eThe 300 l\/mm grating provides half the spectral resolution of the standard 600 l\/mm grating. In exchange, it covers a much wider spectral range on the same sensor. The 600 l\/mm is a general-purpose tool for detailed analysis, while the 300 l\/mm is a specialized tool for wide-field spectroscopic surveys.\u003c\/p\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion\"\u003e\n\u003ch3 class=\"DAV-accordion-Q\"\u003eWhen would I choose the 300 l\/mm grating for observing a nova like Nova Persei (GK Persei)?\u003c\/h3\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion-A\"\u003e\n\u003cp\u003eFor a nova, especially in its early, rapidly evolving stages, the 300 l\/mm grating is an excellent choice. It allows you to capture the entire visible spectrum, including the broad P Cygni profiles and multiple emission lines (like the Balmer series), in a single exposure to monitor its overall evolution. A higher-resolution grating might require multiple exposures and mosaicking to cover the same range.\u003c\/p\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion\"\u003e\n\u003ch3 class=\"DAV-accordion-Q\"\u003eWill the 300 l\/mm grating fit my Shelyak UVEX spectroscope?\u003c\/h3\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion-A\"\u003e\n\u003cp\u003eYes. This grating is specifically designed as an interchangeable module for the Shelyak UVEX spectroscope, allowing you to easily swap it with the standard 600 l\/mm grating or other optional gratings in the series.\u003c\/p\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion\"\u003e\n\u003ch3 class=\"DAV-accordion-Q\"\u003eIs the 300 l\/mm grating better for faint objects than the 1200 l\/mm grating?\u003c\/h3\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion-A\"\u003e\n\u003cp\u003eYes, for capturing a detectable spectrum. The 300 l\/mm grating concentrates the faint light over a smaller area on the sensor, improving the signal-to-noise ratio of the overall spectrum. The 1200 l\/mm grating spreads that same faint light out much further, which can make the resulting high-resolution spectrum too dim to be useful without very long exposures.\u003c\/p\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion\"\u003e\n\u003ch3 class=\"DAV-accordion-Q\"\u003eCan I use the 300 l\/mm grating to measure the redshift of a quasar like 3C 273?\u003c\/h3\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion-A\"\u003e\n\u003cp\u003eYes, this is an excellent application for the 300 l\/mm grating. The broad emission lines of a quasar like 3C 273 are easily visible at this resolution, and the wide spectral coverage helps you identify multiple lines to confirm the redshift. The goal is to identify the pattern of shifted lines, not to resolve their internal structure, making low resolution ideal.\u003c\/p\u003e\n\u003c\/div\u003e\n\u003c\/li\u003e\n\u003cli\u003e\n\u003ctable class=\"DAV-specifications\"\u003e\n\u003ctbody\u003e\n\u003ctr\u003e\n\u003ctd\u003eProduct\u003c\/td\u003e\n\u003ctd\u003eGrating Module\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eInstrument\u003c\/td\u003e\n\u003ctd\u003eShelyak UVEX Spectroscope\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eGrating Density\u003c\/td\u003e\n\u003ctd\u003e300 lines\/mm\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003c\/tbody\u003e\n\u003c\/table\u003e\n\u003c\/li\u003e\n\u003cli\u003e\n\u003cul class=\"DAV-grid\"\u003e\n\u003cli class=\"DAV-grid-item\"\u003e\n\u003cdiv\u003e\n\u003cp class=\"DAV-item-title\"\u003eGrating Module for UVEX (300 l\/mm)\u003c\/p\u003e\n\u003cp class=\"DAV-item-subtitle\"\u003e× 1\u003c\/p\u003e\n\u003c\/div\u003e\n\u003c\/li\u003e\n\u003c\/ul\u003e\n\u003c\/li\u003e\n\u003cli\u003e\n\u003cul class=\"DAV-grid\"\u003e\n\u003cli class=\"DAV-grid-item\"\u003e\u003ca href=\"https:\/\/cdn.shopify.com\/s\/files\/1\/0753\/5280\/1565\/files\/Shelyak_UVEX_Manual.pdf\" target=\"_blank\"\u003e\u003csvg class=\"DAV-img-box\" viewbox=\"0 0 512 512\" xmlns=\"http:\/\/www.w3.org\/2000\/svg\"\u003e\u003cpath d=\"M0 64C0 28.7 28.7 0 64 0L224 0l0 128c0 17.7 14.3 32 32 32l128 0 0 144-208 0c-35.3 0-64 28.7-64 64l0 144-48 0c-35.3 0-64-28.7-64-64L0 64zm384 64l-128 0L256 0 384 128zM176 352l32 0c30.9 0 56 25.1 56 56s-25.1 56-56 56l-16 0 0 32c0 8.8-7.2 16-16 16s-16-7.2-16-16l0-48 0-80c0-8.8 7.2-16 16-16zm32 80c13.3 0 24-10.7 24-24s-10.7-24-24-24l-16 0 0 48 16 0zm96-80l32 0c26.5 0 48 21.5 48 48l0 64c0 26.5-21.5 48-48 48l-32 0c-8.8 0-16-7.2-16-16l0-128c0-8.8 7.2-16 16-16zm32 128c8.8 0 16-7.2 16-16l0-64c0-8.8-7.2-16-16-16l-16 0 0 96 16 0zm80-112c0-8.8 7.2-16 16-16l48 0c8.8 0 16 7.2 16 16s-7.2 16-16 16l-32 0 0 32 32 0c8.8 0 16 7.2 16 16s-7.2 16-16 16l-32 0 0 48c0 8.8-7.2 16-16 16s-16-7.2-16-16l0-64 0-64z\" fill=\"#0047a7\"\u003e\u003c\/path\u003e\u003c\/svg\u003e\n\u003cdiv\u003e\n\u003cp class=\"DAV-item-title\"\u003eShelyak UVEX Manual\u003c\/p\u003e\n\u003c\/div\u003e\n\u003c\/a\u003e\u003c\/li\u003e\n\u003c\/ul\u003e\n\u003c\/li\u003e\n\u003cli\u003e\n\u003ca href=\"https:\/\/davidastro.com\/pages\/shelyak-warranty-policy\" rel=\"noopener\" target=\"_blank\"\u003eShelyak 1-Year Warranty\u003c\/a\u003e\n\u003c\/li\u003e\n\u003c\/ul\u003e","brand":"Shelyak","offers":[{"title":"Default Title","offer_id":52943052275997,"sku":"SHK-SE0243","price":992.0,"currency_code":"CAD","in_stock":true}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0753\/5280\/1565\/files\/Shelyak-Grating-module-for-the-UVEX-150-l-mm-1_b112a085-7d93-4f03-a91a-1d652c44b9a9.jpg?v=1789616467"},{"product_id":"shelyak-se0245","title":"Shelyak Grating module for the UVEX - 1200 l\/mm","description":"\u003cul class=\"DAV-feature-list\"\u003e\n\u003cli\u003e1200 lines\/mm Grating Density\u003c\/li\u003e\n\u003cli\u003eDesigned for the Shelyak UVEX Spectroscope\u003c\/li\u003e\n\u003cli\u003eEnables High-Resolution Spectroscopy\u003c\/li\u003e\n\u003cli\u003eUser-Interchangeable Module\u003c\/li\u003e\n\u003cli\u003eDoubles Resolution of Standard Grating\u003c\/li\u003e\n\u003c\/ul\u003e\n\u003c!-- more --\u003e\n\u003cul class=\"tabs\"\u003e\n\u003cli class=\"active\"\u003eDescription\u003c\/li\u003e\n\u003cli\u003eFAQ\u003c\/li\u003e\n\u003cli\u003eSpecifications\u003c\/li\u003e\n\n\u003cli\u003eDownloads\u003c\/li\u003e\n\u003cli\u003eWarranty\u003c\/li\u003e\n\u003c\/ul\u003e\n\u003cul class=\"tabs-content\"\u003e\n\u003cli class=\"active\"\u003e\n\u003cdiv\u003e\n\u003cdiv class=\"DAV-bg-light\"\u003e\n\u003cdiv class=\"DAV-section-center\"\u003e\n\u003ch2\u003eGrating module for the UVEX - 1200 l\/mm\u003c\/h2\u003e\n\u003cp\u003eThis optional 1200 lines\/mm grating module for the Shelyak UVEX spectroscope is engineered specifically for high-resolution applications. It directly replaces the standard 600 l\/mm grating supplied with the UVEX, effectively doubling the instrument's native spectral resolving power for detailed scientific analysis.\u003c\/p\u003e\n\u003c\/div\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-bg-light\"\u003e\n\u003cdiv class=\"DAV-section\"\u003e\n\u003ch3\u003eHigh-Resolution Spectroscopy with the 1200 l\/mm Grating\u003c\/h3\u003e\n\u003cp\u003eIncreasing a spectroscope's line density from 600 l\/mm to 1200 l\/mm allows you to resolve finer details within a star's spectrum. This is critical for advanced projects such as monitoring the emission line profile changes in Be stars, measuring small Doppler shifts in spectroscopic binaries, or separating closely spaced absorption lines in stellar atmospheres.\u003c\/p\u003e\n\u003cp\u003eBy spreading the light over a greater angle, the 1200 l\/mm grating makes these subtle spectral features large enough for your camera sensor to detect. This module transforms the UVEX into an instrument capable of contributing to pro-am research campaigns that require higher resolving power than the stock configuration can provide.\u003c\/p\u003e\n\u003c\/div\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-bg-light\"\u003e\n\u003cdiv class=\"DAV-section\"\u003e\n\u003ch3\u003eChoosing Your Grating: 1200 l\/mm vs. the 600 l\/mm Standard\u003c\/h3\u003e\n\u003cp\u003eThe primary trade-off for higher resolution is a reduction in the spectral range captured in a single exposure. While the standard 600 l\/mm grating provides a balanced view of a wide wavelength range, the 1200 l\/mm grating focuses on a smaller segment of the spectrum with significantly greater detail.\u003c\/p\u003e\n\u003cul\u003e\n\u003cli\u003e\n\u003cstrong\u003e1200 l\/mm Grating:\u003c\/strong\u003e Choose this for targeted studies of specific spectral lines (like H-alpha or Sodium D-lines) where maximum detail is the goal.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003e600 l\/mm Grating (Standard):\u003c\/strong\u003e Ideal for general stellar classification and capturing broad spectral features across a wide range of wavelengths in one shot.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eLower Density Gratings (e.g., 300 l\/mm):\u003c\/strong\u003e Best for low-resolution survey work, classifying faint objects like supernovae, or capturing the entire visible spectrum of a star at once.\u003c\/li\u003e\n\u003c\/ul\u003e\n\u003c\/div\u003e\n\u003c\/div\u003e\n\u003c\/div\u003e\n\u003c\/li\u003e\n\u003cli\u003e\n\u003cdiv class=\"DAV-accordion\"\u003e\n\u003ch3 class=\"DAV-accordion-Q\"\u003eWhat is the main advantage of the Shelyak 1200 l\/mm grating over the standard 600 l\/mm grating?\u003c\/h3\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion-A\"\u003e\n\u003cp\u003eThe primary advantage is \u003cstrong\u003edoubled spectral resolution\u003c\/strong\u003e. The 1200 l\/mm grating spreads light out more, allowing you to see finer details and separate spectral lines that would appear blended together with the standard 600 l\/mm grating. This is essential for detailed scientific analysis of specific spectral features.\u003c\/p\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion\"\u003e\n\u003ch3 class=\"DAV-accordion-Q\"\u003eWhen should I use a lower resolution grating instead of this 1200 l\/mm module for the UVEX?\u003c\/h3\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion-A\"\u003e\n\u003cp\u003eUse a lower-density grating (like the optional 300 l\/mm or 150 l\/mm) when your priority is capturing the widest possible wavelength range in a single image, or when observing very faint objects. Lower resolution concentrates the light, improving the signal-to-noise ratio for targets like quasars, comets, or faint supernovae where detailed line profiles are less critical than initial classification.\u003c\/p\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion\"\u003e\n\u003ch3 class=\"DAV-accordion-Q\"\u003eCan I use the 1200 l\/mm UVEX grating to study the H-alpha line of Be stars?\u003c\/h3\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion-A\"\u003e\n\u003cp\u003eYes, this is an ideal application. The high resolution of the 1200 l\/mm grating is perfectly suited for resolving the complex and variable emission profiles of the H-alpha line in Be stars. This allows you to track changes in the star's circumstellar disk, which is a key area of pro-am collaborative research.\u003c\/p\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion\"\u003e\n\u003ch3 class=\"DAV-accordion-Q\"\u003eHow does the 1200 l\/mm grating affect the wavelength range I can capture with the UVEX?\u003c\/h3\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion-A\"\u003e\n\u003cp\u003eThe 1200 l\/mm grating significantly \u003cstrong\u003enarrows the spectral range\u003c\/strong\u003e that fits onto your camera's sensor in a single exposure compared to the 600 l\/mm grating. You will be capturing a smaller slice of the spectrum, but with much greater detail within that slice. You may need to take multiple exposures, rotating the grating slightly between each, to cover a wider region of interest.\u003c\/p\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion\"\u003e\n\u003ch3 class=\"DAV-accordion-Q\"\u003eIs installing the 1200 l\/mm grating module in the UVEX spectroscope difficult?\u003c\/h3\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion-A\"\u003e\n\u003cp\u003eNo, the UVEX is designed for interchangeable gratings. The modules are made to be easily swappable by the user, allowing you to change the resolution of the spectroscope in the field to match your observing target and scientific goals for the night.\u003c\/p\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion\"\u003e\n\u003ch3 class=\"DAV-accordion-Q\"\u003eWhat kind of telescope is best for high-resolution spectroscopy with the UVEX and the 1200 l\/mm grating?\u003c\/h3\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion-A\"\u003e\n\u003cp\u003eHigh-resolution spectroscopy requires a strong signal. Therefore, telescopes with larger apertures (typically 8\" or greater) are recommended to gather enough light, especially for fainter stars. Schmidt-Cassegrains (SCTs) and Ritchey-Chrétiens (RCs) are common choices due to their large apertures and comfortable back focus, which easily accommodates the spectroscope.\u003c\/p\u003e\n\u003c\/div\u003e\n\u003c\/li\u003e\n\u003cli\u003e\n\u003ctable class=\"DAV-specifications\"\u003e\n\u003ctbody\u003e\n\u003ctr\u003e\n\u003ctd\u003eGrating Density\u003c\/td\u003e\n\u003ctd\u003e1200 lines\/mm\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eCompatibility\u003c\/td\u003e\n\u003ctd\u003eShelyak UVEX Spectroscope\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003c\/tbody\u003e\n\u003c\/table\u003e\n\u003c\/li\u003e\n\n\u003cli\u003e\n\u003cul class=\"DAV-grid\"\u003e\n\u003cli class=\"DAV-grid-item\"\u003e\u003ca href=\"https:\/\/cdn.shopify.com\/s\/files\/1\/0753\/5280\/1565\/files\/Shelyak_UVEX_Manual.pdf\" target=\"_blank\"\u003e\u003csvg class=\"DAV-img-box\" viewbox=\"0 0 512 512\" xmlns=\"http:\/\/www.w3.org\/2000\/svg\"\u003e\u003cpath d=\"M0 64C0 28.7 28.7 0 64 0L224 0l0 128c0 17.7 14.3 32 32 32l128 0 0 144-208 0c-35.3 0-64 28.7-64 64l0 144-48 0c-35.3 0-64-28.7-64-64L0 64zm384 64l-128 0L256 0 384 128zM176 352l32 0c30.9 0 56 25.1 56 56s-25.1 56-56 56l-16 0 0 32c0 8.8-7.2 16-16 16s-16-7.2-16-16l0-48 0-80c0-8.8 7.2-16 16-16zm32 80c13.3 0 24-10.7 24-24s-10.7-24-24-24l-16 0 0 48 16 0zm96-80l32 0c26.5 0 48 21.5 48 48l0 64c0 26.5-21.5 48-48 48l-32 0c-8.8 0-16-7.2-16-16l0-128c0-8.8 7.2-16 16-16zm32 128c8.8 0 16-7.2 16-16l0-64c0-8.8-7.2-16-16-16l-16 0 0 96 16 0zm80-112c0-8.8 7.2-16 16-16l48 0c8.8 0 16 7.2 16 16s-7.2 16-16 16l-32 0 0 32 32 0c8.8 0 16 7.2 16 16s-7.2 16-16 16l-32 0 0 48c0 8.8-7.2 16-16 16s-16-7.2-16-16l0-64 0-64z\" fill=\"#0047a7\"\u003e\u003c\/path\u003e\u003c\/svg\u003e\n\u003cdiv\u003e\n\u003cp class=\"DAV-item-title\"\u003eShelyak UVEX Manual\u003c\/p\u003e\n\u003c\/div\u003e\n\u003c\/a\u003e\u003c\/li\u003e\n\u003c\/ul\u003e\n\u003c\/li\u003e\n\u003cli\u003e\n\u003ca href=\"https:\/\/davidastro.com\/pages\/shelyak-warranty-policy\" rel=\"noopener\" target=\"_blank\"\u003eShelyak 1-Year Warranty\u003c\/a\u003e\n\u003c\/li\u003e\n\u003c\/ul\u003e","brand":"Shelyak","offers":[{"title":"Default Title","offer_id":52943052538141,"sku":"SHK-SE0245","price":992.0,"currency_code":"CAD","in_stock":true}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0753\/5280\/1565\/files\/Shelyak-Grating-module-for-the-UVEX-150-l-mm-1_bdc204a7-8ffd-43bd-b3b3-805d4a5ab9ff.jpg?v=1789616475"},{"product_id":"shelyak-se0246","title":"Shelyak Grating module for the UVEX - 1800 l\/mm","description":"\u003cul class=\"DAV-feature-list\"\u003e\n\u003cli\u003eGrating Density: 1800 lines\/mm\u003c\/li\u003e\n\u003cli\u003eInstrument Compatibility: Shelyak UVEX Spectroscope\u003c\/li\u003e\n\u003cli\u003ePrimary Application: High-resolution spectroscopy\u003c\/li\u003e\n\u003cli\u003eModular Design: Interchangeable with other UVEX gratings\u003c\/li\u003e\n\u003c\/ul\u003e\n\u003c!-- more --\u003e\n\u003cul class=\"tabs\"\u003e\n\u003cli class=\"active\"\u003eDescription\u003c\/li\u003e\n\u003cli\u003eFAQ\u003c\/li\u003e\n\n\u003cli\u003eDownloads\u003c\/li\u003e\n\u003cli\u003eWarranty\u003c\/li\u003e\n\u003c\/ul\u003e\n\u003cul class=\"tabs-content\"\u003e\n\u003cli class=\"active\"\u003e\n\u003cdiv\u003e\n\u003cdiv class=\"DAV-bg-light\"\u003e\n\u003cdiv class=\"DAV-section-center\"\u003e\n\u003ch2\u003eGrating module for the UVEX - 1800 l\/mm\u003c\/h2\u003e\n\u003cp\u003eThe Shelyak Grating Module for the UVEX elevates your spectroscope's capabilities with a line density of 1800 lines per millimeter (l\/mm). This module offers three times the line count of the standard 600 l\/mm grating included with the UVEX, delivering the highest possible spectral dispersion and resolution available for the instrument.\u003c\/p\u003e\n\u003c\/div\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-bg-light\"\u003e\n\u003cdiv class=\"DAV-section\"\u003e\n\u003ch3\u003e1800 l\/mm: The Highest Resolution for UVEX Spectroscopy\u003c\/h3\u003e\n\u003cp\u003eThis grating is a specialized tool designed for maximum detail. The high 1800 l\/mm density spreads starlight across a greater number of pixels, allowing you to resolve extremely fine spectral features that are invisible with lower-dispersion gratings. It is the ideal choice for advanced projects like measuring the Doppler shift in binary star systems, analyzing the detailed atmospheric lines of bright stars, or separating close emission lines in planetary nebulae.\u003c\/p\u003e\n\u003cp\u003eThe trade-off for this high resolution is a reduction in brightness and a narrower spectral range captured in a single exposure. This makes the 1800 l\/mm grating best suited for brighter targets where photon signal is abundant and fine detail is the primary scientific goal.\u003c\/p\u003e\n\u003c\/div\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-bg-light\"\u003e\n\u003cdiv class=\"DAV-section\"\u003e\n\u003ch3\u003eThe 5-Grating UVEX Modular System\u003c\/h3\u003e\n\u003cp\u003eThe UVEX spectroscope is engineered around a modular, user-interchangeable grating system. This allows you to adapt the instrument's resolution to match your specific target and observing conditions. The 1800 l\/mm grating represents the pinnacle of this system for high-resolution work.\u003c\/p\u003e\n\u003cp\u003eYou can easily swap it with the standard 600 l\/mm grating or other optional modules, including the 150, 300, and 1200 l\/mm versions. This flexibility transforms the UVEX from a single instrument into a versatile analytical platform, capable of everything from low-resolution surveys of faint objects to high-precision analysis of bright stars.\u003c\/p\u003e\n\u003c\/div\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-bg-light\"\u003e\n\u003cdiv class=\"DAV-section\"\u003e\n\u003ch3\u003e1800 l\/mm vs. 600 l\/mm: Choosing the Right Dispersion\u003c\/h3\u003e\n\u003cp\u003eSelecting the correct grating is critical for successful spectroscopy. The choice between the optional 1800 l\/mm module and the standard 600 l\/mm grating depends entirely on your target.\u003c\/p\u003e\n\u003cul\u003e\n\u003cli\u003e\n\u003cstrong\u003eStandard 600 l\/mm Grating:\u003c\/strong\u003e This is the workhorse for general spectroscopy. It produces brighter spectra and captures a wider range of wavelengths in one shot, making it ideal for classifying stars, observing fainter objects like supernovae, or conducting initial survey work.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eOptional 1800 l\/mm Grating:\u003c\/strong\u003e This is a specialist's tool. Use it when you have a bright target and a specific scientific question that requires resolving very fine details. It prioritizes resolution over all other factors.\u003c\/li\u003e\n\u003c\/ul\u003e\n\u003c\/div\u003e\n\u003c\/div\u003e\n\u003c\/div\u003e\n\u003c\/li\u003e\n\u003cli\u003e\n\u003cdiv class=\"DAV-accordion\"\u003e\n\u003ch3 class=\"DAV-accordion-Q\"\u003eWhat is the primary advantage of the 1800 l\/mm grating for the UVEX?\u003c\/h3\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion-A\"\u003e\n\u003cp\u003eThe primary advantage is its \u003cstrong\u003ehigh spectral resolution\u003c\/strong\u003e. With 1800 lines per millimeter, it spreads light out more than any other UVEX grating, allowing you to resolve very fine, closely spaced details in a spectrum that would be blurred together at lower dispersions.\u003c\/p\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion\"\u003e\n\u003ch3 class=\"DAV-accordion-Q\"\u003eWhen would I use the 1800 l\/mm grating to observe a star like Vega (Alpha Lyrae)?\u003c\/h3\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion-A\"\u003e\n\u003cp\u003eFor a bright A-type star like Vega, the 1800 l\/mm grating would be excellent for studying the detailed profile of its prominent hydrogen absorption lines (the Balmer series). The high resolution would allow you to detect subtle asymmetries or Doppler shifts caused by stellar rotation or other atmospheric phenomena.\u003c\/p\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion\"\u003e\n\u003ch3 class=\"DAV-accordion-Q\"\u003eDoes using the 1800 l\/mm grating have any disadvantages compared to the standard 600 l\/mm?\u003c\/h3\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion-A\"\u003e\n\u003cp\u003eYes. Because the light is spread out more, the resulting spectrum is \u003cstrong\u003edimmer\u003c\/strong\u003e and covers a \u003cstrong\u003enarrower wavelength range\u003c\/strong\u003e in a single image. This means it requires longer exposure times or brighter targets and may require taking multiple images to cover the same spectral range as the 600 l\/mm grating.\u003c\/p\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion\"\u003e\n\u003ch3 class=\"DAV-accordion-Q\"\u003eHow difficult is it to install the 1800 l\/mm grating module in the UVEX spectroscope?\u003c\/h3\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion-A\"\u003e\n\u003cp\u003eThe UVEX is designed for user-swappable gratings. The process is straightforward and involves removing the access panel and carefully exchanging the modules. For detailed instructions, please refer to the main Shelyak UVEX instrument manual.\u003c\/p\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion\"\u003e\n\u003ch3 class=\"DAV-accordion-Q\"\u003eCan I use the UVEX 1800 l\/mm grating to study a faint galaxy like the Whirlpool Galaxy (M51)?\u003c\/h3\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion-A\"\u003e\n\u003cp\u003eIt is not recommended. The high dispersion of the 1800 l\/mm grating would spread the very faint light from M51 too thinly, resulting in an unusable spectrum with a very low signal-to-noise ratio. A low-dispersion grating, like the standard 600 l\/mm or optional 150 l\/mm, is required for such faint, extended objects.\u003c\/p\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion\"\u003e\n\u003ch3 class=\"DAV-accordion-Q\"\u003eWhat other gratings are available for the Shelyak UVEX?\u003c\/h3\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion-A\"\u003e\n\u003cp\u003eThe UVEX modular system includes a family of gratings to suit different scientific goals. In addition to the standard 600 l\/mm and this 1800 l\/mm module, Shelyak offers optional gratings of \u003cstrong\u003e150 l\/mm\u003c\/strong\u003e, \u003cstrong\u003e300 l\/mm\u003c\/strong\u003e, and \u003cstrong\u003e1200 l\/mm\u003c\/strong\u003e.\u003c\/p\u003e\n\u003c\/div\u003e\n\u003c\/li\u003e\n\n\u003cli\u003e\n\u003cul class=\"DAV-grid\"\u003e\n\u003cli class=\"DAV-grid-item\"\u003e\u003ca href=\"https:\/\/cdn.shopify.com\/s\/files\/1\/0753\/5280\/1565\/files\/Shelyak_UVEX_Manual.pdf\" target=\"_blank\"\u003e\u003csvg class=\"DAV-img-box\" viewbox=\"0 0 512 512\" xmlns=\"http:\/\/www.w3.org\/2000\/svg\"\u003e\u003cpath d=\"M0 64C0 28.7 28.7 0 64 0L224 0l0 128c0 17.7 14.3 32 32 32l128 0 0 144-208 0c-35.3 0-64 28.7-64 64l0 144-48 0c-35.3 0-64-28.7-64-64L0 64zm384 64l-128 0L256 0 384 128zM176 352l32 0c30.9 0 56 25.1 56 56s-25.1 56-56 56l-16 0 0 32c0 8.8-7.2 16-16 16s-16-7.2-16-16l0-48 0-80c0-8.8 7.2-16 16-16zm32 80c13.3 0 24-10.7 24-24s-10.7-24-24-24l-16 0 0 48 16 0zm96-80l32 0c26.5 0 48 21.5 48 48l0 64c0 26.5-21.5 48-48 48l-32 0c-8.8 0-16-7.2-16-16l0-128c0-8.8 7.2-16 16-16zm32 128c8.8 0 16-7.2 16-16l0-64c0-8.8-7.2-16-16-16l-16 0 0 96 16 0zm80-112c0-8.8 7.2-16 16-16l48 0c8.8 0 16 7.2 16 16s-7.2 16-16 16l-32 0 0 32 32 0c8.8 0 16 7.2 16 16s-7.2 16-16 16l-32 0 0 48c0 8.8-7.2 16-16 16s-16-7.2-16-16l0-64 0-64z\" fill=\"#0047a7\"\u003e\u003c\/path\u003e\u003c\/svg\u003e\n\u003cdiv\u003e\n\u003cp class=\"DAV-item-title\"\u003eShelyak UVEX Manual\u003c\/p\u003e\n\u003c\/div\u003e\n\u003c\/a\u003e\u003c\/li\u003e\n\u003c\/ul\u003e\n\u003c\/li\u003e\n\u003cli\u003e\n\u003ca href=\"https:\/\/davidastro.com\/pages\/shelyak-warranty-policy\" rel=\"noopener\" target=\"_blank\"\u003eShelyak 1-Year Warranty\u003c\/a\u003e\n\u003c\/li\u003e\n\u003c\/ul\u003e","brand":"Shelyak","offers":[{"title":"Default Title","offer_id":52943052800285,"sku":"SHK-SE0246","price":992.0,"currency_code":"CAD","in_stock":true}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0753\/5280\/1565\/files\/Shelyak-Grating-module-for-the-UVEX-150-l-mm-1_3dc2d9fa-d61e-4483-9460-b6cf48cfa251.jpg?v=1789616483"},{"product_id":"shelyak-se0247","title":"Shelyak High Performance 23µm Slit","description":"\u003cul class=\"DAV-feature-list\"\u003e\n\u003cli\u003e23µm Slit Width\u003c\/li\u003e\n\u003cli\u003eOver 90% Reflectivity\u003c\/li\u003e\n\u003cli\u003eProtected Aluminum Coating\u003c\/li\u003e\n\u003cli\u003e350-800nm Anti-Reflection Coating\u003c\/li\u003e\n\u003cli\u003eCompatible with ALPY 600 \u0026amp; UVEX Spectroscopes\u003c\/li\u003e\n\u003c\/ul\u003e\n\u003c!-- more --\u003e\n\u003cul class=\"tabs\"\u003e\n\u003cli class=\"active\"\u003eDescription\u003c\/li\u003e\n\u003cli\u003eFAQ\u003c\/li\u003e\n\u003cli\u003eSpecifications\u003c\/li\u003e\n\u003cli\u003eIn the Box\u003c\/li\u003e\n\u003cli\u003eWarranty\u003c\/li\u003e\n\u003c\/ul\u003e\n\u003cul class=\"tabs-content\"\u003e\n\u003cli class=\"active\"\u003e\n\u003cdiv\u003e\n\u003cdiv class=\"DAV-bg-light\"\u003e\n\u003cdiv class=\"DAV-section-center\"\u003e\n\u003ch2\u003eShelyak High Performance 23µm Slit\u003c\/h2\u003e\n\u003cp\u003eThe Shelyak High Performance 23µm Slit replaces standard spectroscope slits with a protected aluminum coating that achieves over 90% reflectivity, a significant increase over the ~50% rate of typical chrome slits. Its anti-reflection treatment is extended to cover the 350-800nm spectral range, making it a critical upgrade for Shelyak ALPY 600 and UVEX spectroscopes.\u003c\/p\u003e\n\u003c\/div\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-bg-light\"\u003e\n\u003cdiv class=\"DAV-section\"\u003e\n\u003ch3\u003eProtected Aluminum Coating: Over 90% Reflectivity\u003c\/h3\u003e\n\u003cp\u003eBy using a protected aluminum coating, this 23µm slit achieves a reflection rate of over 90%. This nearly doubles the light reflected to your guide camera compared to standard chrome slits, which typically reflect only around 50% of the light, leading to more stable and accurate guiding.\u003c\/p\u003e\n\u003cp\u003eThis slit also features a larger reflective surface, which is particularly beneficial when using guide cameras with larger sensors, such as the IMX174, with an Alpy guiding module, ensuring full illumination of the sensor.\u003c\/p\u003e\n\u003c\/div\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-bg-light\"\u003e\n\u003cdiv class=\"DAV-section\"\u003e\n\u003ch3\u003e350-800nm AR Coating for UVEX \u0026amp; ALPY 600\u003c\/h3\u003e\n\u003cp\u003eThe anti-reflection treatment has been optimized for a broad 350-800nm spectral range. This enhancement is especially critical for the UVEX spectroscope, allowing you to maintain high signal-to-noise across its entire operational range, from the near-ultraviolet to the near-infrared.\u003c\/p\u003e\n\u003cp\u003eThis slit is a direct-fit upgrade for both the Shelyak ALPY 600 and UVEX spectroscopes. It is the recommended slit for any UVEX user seeking to maximize instrument throughput and scientific output.\u003c\/p\u003e\n\u003c\/div\u003e\n\u003c\/div\u003e\n\u003c\/div\u003e\n\u003c\/li\u003e\n\u003cli\u003e\n\u003cdiv class=\"DAV-accordion\"\u003e\n\u003ch3 class=\"DAV-accordion-Q\"\u003eWhat is the main advantage of the Shelyak High Performance 23µm Slit over a standard one?\u003c\/h3\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion-A\"\u003e\n\u003cp\u003eThe primary benefit is its reflectivity of \u003cstrong\u003eover 90%\u003c\/strong\u003e from its protected aluminum coating, compared to ~50% for standard chrome slits. This sends significantly more light to your guide camera, improving guiding accuracy on fainter stars.\u003c\/p\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion\"\u003e\n\u003ch3 class=\"DAV-accordion-Q\"\u003eI use a Shelyak UVEX spectroscope to study Be stars. Is this 23µm slit a good choice?\u003c\/h3\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion-A\"\u003e\n\u003cp\u003eYes, it is highly recommended for the UVEX. Its extended \u003cstrong\u003eanti-reflection coating (350-800nm)\u003c\/strong\u003e ensures maximum light throughput across the UVEX's wide spectral range, which is ideal for capturing both the Balmer lines in the visible and other features toward the UV and NIR ends of the spectrum.\u003c\/p\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion\"\u003e\n\u003ch3 class=\"DAV-accordion-Q\"\u003eWill the High Performance 23µm Slit work with my ALPY 600 and an IMX174 guide camera?\u003c\/h3\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion-A\"\u003e\n\u003cp\u003eAbsolutely. The slit is fully compatible with the \u003cstrong\u003eALPY 600\u003c\/strong\u003e. It also features a larger reflective surface specifically to better accommodate larger sensors like the IMX174, ensuring the guide star is not vignetted.\u003c\/p\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion\"\u003e\n\u003ch3 class=\"DAV-accordion-Q\"\u003eWhat material is the coating on the High Performance 23µm Slit?\u003c\/h3\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion-A\"\u003e\n\u003cp\u003eThe slit features a \u003cstrong\u003eprotected aluminum\u003c\/strong\u003e coating. This material provides the high reflectivity (\u0026gt;90%) and durability required for spectrographic applications.\u003c\/p\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion\"\u003e\n\u003ch3 class=\"DAV-accordion-Q\"\u003eIs the 23µm High Performance Slit compatible with other spectroscopes?\u003c\/h3\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion-A\"\u003e\n\u003cp\u003eThis slit is specifically designed and confirmed to be compatible with the \u003cstrong\u003eShelyak ALPY 600\u003c\/strong\u003e and \u003cstrong\u003eShelyak UVEX\u003c\/strong\u003e spectroscopes. Compatibility with other models is not guaranteed.\u003c\/p\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion\"\u003e\n\u003ch3 class=\"DAV-accordion-Q\"\u003eWhy is the anti-reflection coating on the High Performance 23µm Slit important?\u003c\/h3\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion-A\"\u003e\n\u003cp\u003eThe anti-reflection coating minimizes light loss as it passes through the slit into the spectroscope. By extending this coating to cover \u003cstrong\u003e350-800nm\u003c\/strong\u003e, the slit ensures that more photons from your target reach the science camera, improving the signal-to-noise ratio of your final spectrum.\u003c\/p\u003e\n\u003c\/div\u003e\n\u003c\/li\u003e\n\u003cli\u003e\n\u003ctable class=\"DAV-specifications\"\u003e\n\u003ctbody\u003e\n\u003ctr\u003e\n\u003ctd\u003eSlit Width\u003c\/td\u003e\n\u003ctd\u003e23µm\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eCoating\u003c\/td\u003e\n\u003ctd\u003eProtected Aluminum\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eReflectivity\u003c\/td\u003e\n\u003ctd\u003e\u0026gt; 90%\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eAnti-Reflection Range\u003c\/td\u003e\n\u003ctd\u003e350-800nm\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eCompatibility\u003c\/td\u003e\n\u003ctd\u003eShelyak ALPY 600, Shelyak UVEX\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003c\/tbody\u003e\n\u003c\/table\u003e\n\u003c\/li\u003e\n\u003cli\u003e\n\u003cul class=\"DAV-grid\"\u003e\n\u003cli class=\"DAV-grid-item\"\u003e\n\u003cdiv\u003e\n\u003cp class=\"DAV-item-title\"\u003eHigh Performance Slit 23µm\u003c\/p\u003e\n\u003cp class=\"DAV-item-subtitle\"\u003e× 1\u003c\/p\u003e\n\u003c\/div\u003e\n\u003c\/li\u003e\n\u003c\/ul\u003e\n\u003c\/li\u003e\n\u003cli\u003e\n\u003ca href=\"https:\/\/davidastro.com\/pages\/shelyak-warranty-policy\" rel=\"noopener\" target=\"_blank\"\u003eShelyak 1-Year Warranty\u003c\/a\u003e\n\u003c\/li\u003e\n\u003c\/ul\u003e","brand":"Shelyak","offers":[{"title":"Default Title","offer_id":52943053062429,"sku":"SHK-SE0247","price":499.0,"currency_code":"CAD","in_stock":true}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0753\/5280\/1565\/files\/Shelyak-High-performance-slit-23-m-1_1cd135c0-60a7-4666-9974-c8af022f25de.jpg?v=1789616492"},{"product_id":"shelyak-se0253","title":"Shelyak 10 µm Mirror Slit for Shelyak Spectrographs","description":"\u003cul class=\"DAV-feature-list\"\u003e\n\u003cli\u003e10 µm Slit Width\u003c\/li\u003e\n\u003cli\u003eHigh-Reflectivity Mirror Finish\u003c\/li\u003e\n\u003cli\u003eCompatible with Shelyak Alpy Spectrographs\u003c\/li\u003e\n\u003cli\u003eCompatible with Shelyak UVEX Spectrographs\u003c\/li\u003e\n\u003cli\u003eCompatible with Shelyak Sol'Ex Spectrographs\u003c\/li\u003e\n\u003c\/ul\u003e\n\u003c!-- more --\u003e\n\u003cul class=\"tabs\"\u003e\n\u003cli class=\"active\"\u003eDescription\u003c\/li\u003e\n\u003cli\u003eFAQ\u003c\/li\u003e\n\u003cli\u003eSpecifications\u003c\/li\u003e\n\u003cli\u003eIn the Box\u003c\/li\u003e\n\u003cli\u003eWarranty\u003c\/li\u003e\n\u003c\/ul\u003e\n\n\u003cul class=\"tabs-content\"\u003e\n\u003cli class=\"active\"\u003e\n\u003cdiv\u003e\n  \u003cdiv class=\"DAV-bg-light\"\u003e\n    \u003cdiv class=\"DAV-section-center\"\u003e\n      \u003ch2\u003e10 µm Mirror Slit for Shelyak Spectrographs\u003c\/h2\u003e\n      \u003cp\u003eThis 10 µm mirror slit is an optional accessory engineered for achieving the highest possible spectral resolution with Shelyak Alpy, UVEX, and Sol'Ex spectrographs. By narrowing the input aperture to just 10 µm, this slit allows you to resolve fine details in stellar spectra that are inaccessible with wider, standard-issue slits.\u003c\/p\u003e\n    \u003c\/div\u003e\n  \u003c\/div\u003e\n\n  \u003cdiv class=\"DAV-bg-light\"\u003e\n    \u003cdiv class=\"DAV-section\"\u003e\n      \u003ch3\u003eThe 10 µm Slit: Maximizing Spectral Resolution for Alpy, UVEX, and Sol'Ex\u003c\/h3\u003e\n      \u003cp\u003eIn spectroscopy, the width of the entrance slit is a primary factor controlling spectral resolution. This 10 µm slit provides a significantly narrower aperture than the standard slits included with most spectrographs, directly translating to a higher resolving power. This is critical for scientific applications like measuring the Doppler shift of close binary stars or identifying subtle absorption features in the atmospheres of Be stars.\u003c\/p\u003e\n      \u003cp\u003eThe mirror finish serves a dual purpose: it reflects over 95% of the starlight that does not pass through the slit back to your guide camera, making target centering and guiding significantly easier. This is especially important when using such a narrow slit, as precise alignment on the target is paramount for maintaining signal.\u003c\/p\u003e\n    \u003c\/div\u003e\n  \u003c\/div\u003e\n\n  \u003cdiv class=\"DAV-bg-light\"\u003e\n    \u003cdiv class=\"DAV-section\"\u003e\n      \u003ch3\u003eChoosing the Right Slit: The 10 µm vs. 23 µm Trade-Off\u003c\/h3\u003e\n      \u003cp\u003eWhile the 10 µm slit maximizes resolution, it does so at the cost of light throughput. It is the ideal choice for bright targets under conditions of excellent atmospheric seeing. For fainter objects or nights with poor seeing, a wider slit is often a more practical choice.\u003c\/p\u003e\n      \u003cul\u003e\n        \u003cli\u003e\n          \u003cstrong\u003e10 µm Slit:\u003c\/strong\u003e Best for high-resolution studies of bright stars (Magnitude 6 or brighter), solar spectroscopy with Sol'Ex, and separating close spectral lines. Requires excellent guiding and stable seeing conditions.\u003c\/li\u003e\n        \u003cli\u003e\n          \u003cstrong\u003eStandard 23 µm Slit:\u003c\/strong\u003e A better all-around option for general spectroscopy, fainter targets like quasars and nebulae, and nights of average seeing. It gathers more light, improving the signal-to-noise ratio on faint sources at the expense of lower resolution.\u003c\/li\u003e\n      \u003c\/ul\u003e\n    \u003c\/div\u003e\n  \u003c\/div\u003e\n\n\u003c\/div\u003e\n\u003c\/li\u003e\n\n\u003cli\u003e\n  \u003cdiv class=\"DAV-accordion\"\u003e\n    \u003ch3 class=\"DAV-accordion-Q\"\u003eWhat is the primary advantage of the 10 µm mirror slit for a Shelyak spectrograph?\u003c\/h3\u003e\n  \u003c\/div\u003e\n  \u003cdiv class=\"DAV-accordion-A\"\u003e\n    \u003cp\u003eThe primary advantage is \u003cstrong\u003emaximum spectral resolution\u003c\/strong\u003e. The 10 µm width allows the spectrograph, whether it's an Alpy, UVEX, or Sol'Ex, to resolve finer details in a spectrum compared to wider slits. This is essential for scientific work where separating closely spaced emission or absorption lines is the main objective.\u003c\/p\u003e\n  \u003c\/div\u003e\n  \u003cdiv class=\"DAV-accordion\"\u003e\n    \u003ch3 class=\"DAV-accordion-Q\"\u003eWhen should I use the 10 µm slit instead of the standard 23 µm slit on my Alpy 600?\u003c\/h3\u003e\n  \u003c\/div\u003e\n  \u003cdiv class=\"DAV-accordion-A\"\u003e\n    \u003cp\u003eYou should use the 10 µm slit on your Alpy 600 when observing \u003cstrong\u003ebright stars under excellent seeing conditions\u003c\/strong\u003e. For example, when attempting to split the sodium D lines or measuring the radial velocity of a star like Vega (Alpha Lyrae), the 10 µm slit will provide the best results. For fainter deep-sky objects or nights with turbulent seeing, the 23 µm slit is a better choice as it will collect more light and be more forgiving of guiding errors.\u003c\/p\u003e\n  \u003c\/div\u003e\n    \u003cdiv class=\"DAV-accordion\"\u003e\n    \u003ch3 class=\"DAV-accordion-Q\"\u003eWill the 10 µm slit make my spectra dimmer?\u003c\/h3\u003e\n  \u003c\/div\u003e\n  \u003cdiv class=\"DAV-accordion-A\"\u003e\n    \u003cp\u003eYes. A narrower slit physically blocks more of the star's light from entering the spectrograph. The 10 µm slit will result in a lower signal-to-noise ratio for a given exposure time compared to a wider slit. This trade-off is fundamental: you exchange brightness for higher resolution.\u003c\/p\u003e\n  \u003c\/div\u003e\n  \u003cdiv class=\"DAV-accordion\"\u003e\n    \u003ch3 class=\"DAV-accordion-Q\"\u003eHow does seeing affect performance with the 10 µm slit when observing binary stars like Albireo?\u003c\/h3\u003e\n  \u003c\/div\u003e\n  \u003cdiv class=\"DAV-accordion-A\"\u003e\n    \u003cp\u003ePoor seeing (atmospheric turbulence) causes the star's image to blur and wander. With a very narrow 10 µm slit, the star's image can easily move partially or completely off the slit, causing dramatic drops in signal and making it very difficult to acquire a usable spectrum. For this reason, the 10 µm slit is recommended only for nights with stable, calm air, where the star's image remains small and steady on the slit.\u003c\/p\u003e\n  \u003c\/div\u003e\n    \u003cdiv class=\"DAV-accordion\"\u003e\n    \u003ch3 class=\"DAV-accordion-Q\"\u003eIs the 10 µm slit compatible with all Alpy, UVEX, and Sol'Ex models?\u003c\/h3\u003e\n  \u003c\/div\u003e\n  \u003cdiv class=\"DAV-accordion-A\"\u003e\n    \u003cp\u003eYes, this slit is designed to be fully compatible with the standard slit holders used in the Shelyak Instruments \u003cstrong\u003eAlpy\u003c\/strong\u003e, \u003cstrong\u003eUVEX\u003c\/strong\u003e, and \u003cstrong\u003eSol'Ex\u003c\/strong\u003e spectrograph families. It can be interchanged with other slits of different widths depending on your observing goals.\u003c\/p\u003e\n  \u003c\/div\u003e\n    \u003cdiv class=\"DAV-accordion\"\u003e\n    \u003ch3 class=\"DAV-accordion-Q\"\u003eDoes this 10 µm slit require special focusing or guiding procedures?\u003c\/h3\u003e\n  \u003c\/div\u003e\n  \u003cdiv class=\"DAV-accordion-A\"\u003e\n    \u003cp\u003eYes, it demands more precision. You must achieve critical focus of the star on the slit plane itself. Because the slit is so narrow, guiding must be very accurate to keep the star centered. The mirror surface of the slit greatly aids in this, as it reflects the surrounding starfield back to your autoguider, allowing you to guide directly on the target star's position relative to the slit.\u003c\/p\u003e\n  \u003c\/div\u003e\n\u003c\/li\u003e\n\n\u003cli\u003e\n  \u003ctable class=\"DAV-specifications\"\u003e\n    \u003ctbody\u003e\n      \u003ctr\u003e\n\u003ctd\u003eSlit Width\u003c\/td\u003e\n\u003ctd\u003e10 µm\u003c\/td\u003e\n\u003c\/tr\u003e\n      \u003ctr\u003e\n\u003ctd\u003eCompatibility\u003c\/td\u003e\n\u003ctd\u003eShelyak Alpy, UVEX, Sol'Ex\u003c\/td\u003e\n\u003c\/tr\u003e\n      \u003ctr\u003e\n\u003ctd\u003eType\u003c\/td\u003e\n\u003ctd\u003eReflective Mirror Slit\u003c\/td\u003e\n\u003c\/tr\u003e\n    \u003c\/tbody\u003e\n  \u003c\/table\u003e\n\u003c\/li\u003e\n\n\u003cli\u003e\n  \u003cul class=\"DAV-grid\"\u003e\n    \u003cli class=\"DAV-grid-item\"\u003e\n      \u003cdiv\u003e\n        \u003cp class=\"DAV-item-title\"\u003e10 µm Mirror Slit\u003c\/p\u003e\n        \u003cp class=\"DAV-item-subtitle\"\u003e× 1\u003c\/p\u003e\n      \u003c\/div\u003e\n    \u003c\/li\u003e\n  \u003c\/ul\u003e\n\u003c\/li\u003e\n\n\u003cli\u003e\n\u003ca href=\"https:\/\/davidastro.com\/pages\/shelyak-warranty-policy\" rel=\"noopener\" target=\"_blank\"\u003eShelyak 1-Year Warranty\u003c\/a\u003e\n\u003c\/li\u003e\n\u003c\/ul\u003e","brand":"Shelyak","offers":[{"title":"Default Title","offer_id":52943053914397,"sku":"SHK-SE0253","price":177.0,"currency_code":"CAD","in_stock":true}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0753\/5280\/1565\/files\/Shelyak-10-m-mirror-slit-1_80ed63aa-2dcc-4012-b163-9fb751695000.jpg?v=1789616509"},{"product_id":"shelyak-se0288","title":"Shelyak Star’Ex 14-20-26-32 µm slit + 25 µm hole (GEN2)","description":"\u003cul class=\"DAV-feature-list\"\u003e\n\u003cli\u003eFour selectable slit widths: 14 µm, 20 µm, 26 µm, and 32 µm\u003c\/li\u003e\n\u003cli\u003eCentral 25 µm pinhole for alignment\u003c\/li\u003e\n\u003cli\u003e4mm slit length for extended objects\u003c\/li\u003e\n\u003cli\u003e16mm x 16mm fused silica substrate\u003c\/li\u003e\n\u003cli\u003e2mm substrate thickness for durability\u003c\/li\u003e\n\u003c\/ul\u003e\n\u003c!-- more --\u003e\n\u003cul class=\"tabs\"\u003e\n\u003cli class=\"active\"\u003eDescription\u003c\/li\u003e\n\u003cli\u003eFAQ\u003c\/li\u003e\n\u003cli\u003eSpecifications\u003c\/li\u003e\n\u003cli\u003eIn the Box\u003c\/li\u003e\n\u003cli\u003eWarranty\u003c\/li\u003e\n\u003c\/ul\u003e\n\u003cul class=\"tabs-content\"\u003e\n\u003cli class=\"active\"\u003e\n\u003cdiv\u003e\n\u003cdiv class=\"DAV-bg-light\"\u003e\n\u003cdiv class=\"DAV-section-center\"\u003e\n\u003ch2\u003eStar’Ex 14-20-26-32 µm slit + 25 µm hole (GEN2)\u003c\/h2\u003e\n\u003cp\u003eThe Star’Ex GEN2 4-position reflective slit provides four distinct slit widths—14 µm, 20 µm, 26 µm, and 32 µm—engraved on a 16mm square substrate using high-precision photolithography. A central 25 µm pinhole acts as an artificial star for easy setup, and the entire 2mm thick component is made from robust fused silica for extended spectral transparency down to 375 nanometers. Each 4mm long slit is widened by a factor of 10 at its end to facilitate advanced spectrophotometric calibration.\u003c\/p\u003e\n\u003c\/div\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-bg-light\"\u003e\n\u003cdiv class=\"DAV-section\"\u003e\n\u003ch3\u003eFour Slit Options from 14 µm to 32 µm for Versatile Spectroscopy\u003c\/h3\u003e\n\u003cp\u003eThis second-generation slit offers four distinct apertures arranged in a square, allowing you to match the spectrograph's resolution to your target and seeing conditions. The narrow 14 µm slit is ideal for achieving very high spectral resolution on bright targets with a small telescope. In contrast, the wider 32 µm slit is better suited for low-resolution work or capturing faint signal with larger instruments, such as a 300 mm telescope, where maximizing light input is critical.\u003c\/p\u003e\n\u003c\/div\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-bg-light\"\u003e\n\u003cdiv class=\"DAV-section\"\u003e\n\u003ch3\u003e2mm Fused Silica Construction with UV Transparency\u003c\/h3\u003e\n\u003cp\u003eThe substrate is a 2mm thick, 16mm square blade of fused silica (synthetic quartz), chosen for its exceptional durability and broad spectral transmission. This material is transparent deep into the ultraviolet, offering a modest but useful gain around 375 nanometers even with the standard Star'Ex optics. The 2mm thickness makes the slit robust against mishandling and allows both sides to be cleaned easily with a dampened cotton swab.\u003c\/p\u003e\n\u003c\/div\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-bg-light\"\u003e\n\u003cdiv class=\"DAV-section\"\u003e\n\u003ch3\u003eIntegrated 25 µm Pinhole: An Artificial Star for Easy Benchtop Setup\u003c\/h3\u003e\n\u003cp\u003eA major innovation of the GEN2 design is the central 25 µm diameter hole. This pinhole acts as a perfect artificial star, allowing you to fully align and focus your spectrograph on a workbench without needing a telescope or a clear night sky. This feature dramatically simplifies the initial setup and calibration process, ensuring your instrument is perfectly configured before you attach it to the telescope.\u003c\/p\u003e\n\u003c\/div\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-bg-light\"\u003e\n\u003cdiv class=\"DAV-section\"\u003e\n\u003ch3\u003e4mm Length and Widened Ends for Advanced Spectrophotometry\u003c\/h3\u003e\n\u003cp\u003eEach slit is 4mm long, enabling you to capture spectra from extended objects like nebulae or comets. Furthermore, the final 0.5mm of each slit is widened by a factor of 10. This unique design provides critical data on atmospheric turbulence and instrument performance, and it is essential for acquiring the spectrophotometric data needed to calibrate your spectra in absolute flux values.\u003c\/p\u003e\n\u003c\/div\u003e\n\u003c\/div\u003e\n\u003c\/div\u003e\n\u003c\/li\u003e\n\u003cli\u003e\n\u003cdiv class=\"DAV-accordion\"\u003e\n\u003ch3 class=\"DAV-accordion-Q\"\u003eWhat are the different slit widths on the Star’Ex GEN2 slit for?\u003c\/h3\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion-A\"\u003e\n\u003cp\u003eThe four widths allow you to optimize your spectrograph for different goals.\n\u003c\/p\u003e\n\u003cul\u003e\n\u003cli\u003e\n\u003cstrong\u003e14 µm \u0026amp; 20 µm:\u003c\/strong\u003e Best for high-resolution spectroscopy on bright stars where fine spectral detail is the priority.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003e26 µm \u0026amp; 32 µm:\u003c\/strong\u003e Ideal for lower-resolution work on fainter objects or with larger telescopes, as they allow more light to enter the spectrograph.\u003c\/li\u003e\n\u003c\/ul\u003e\n\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion\"\u003e\n\u003ch3 class=\"DAV-accordion-Q\"\u003eWhat is the purpose of the 25 µm central hole on the Star'Ex GEN2 slit?\u003c\/h3\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion-A\"\u003e\n\u003cp\u003eThe \u003cstrong\u003e25 µm central hole\u003c\/strong\u003e serves as an artificial star. It allows you to perform a complete optical setup and alignment of your spectrograph on a workbench with a simple light source, without needing to attach it to a telescope. This makes initial configuration significantly easier and more precise.\u003c\/p\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion\"\u003e\n\u003ch3 class=\"DAV-accordion-Q\"\u003eHow would I choose between the 14 µm and 32 µm slits for a 300 mm telescope?\u003c\/h3\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion-A\"\u003e\n\u003cp\u003eFor a 300 mm telescope, the \u003cstrong\u003e32 µm slit\u003c\/strong\u003e is generally the better choice. Its wider aperture is better matched to the typical seeing conditions and image scale of a larger instrument, allowing more light from your target to pass into the spectrograph. The 14 µm slit would be extremely difficult to use under average seeing and would discard most of the starlight.\u003c\/p\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion\"\u003e\n\u003ch3 class=\"DAV-accordion-Q\"\u003eWhat is the Star'Ex GEN2 slit made of and why does it matter?\u003c\/h3\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion-A\"\u003e\n\u003cp\u003eThe slit is made from a \u003cstrong\u003e2mm thick plate of fused silica\u003c\/strong\u003e. This material offers two key advantages:\n\u003c\/p\u003e\n\u003cul\u003e\n\u003cli\u003e\n\u003cstrong\u003eDurability:\u003c\/strong\u003e It is mechanically robust and easy to clean without risk of damage.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eUV Transparency:\u003c\/strong\u003e It transmits light well into the ultraviolet portion of the spectrum (down to ~375 nm), allowing for astrophysical studies in wavelengths that are inaccessible with standard glass.\u003c\/li\u003e\n\u003c\/ul\u003e\n\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion\"\u003e\n\u003ch3 class=\"DAV-accordion-Q\"\u003eDoes the Star’Ex GEN2 slit come with a holder?\u003c\/h3\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion-A\"\u003e\n\u003cp\u003eNo, the slit is delivered without its 3D-printed support. You will need to either 3D print the support part yourself using the plans provided by the manufacturer or design a custom holder for your specific instrument.\u003c\/p\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion\"\u003e\n\u003ch3 class=\"DAV-accordion-Q\"\u003eCan I use the 4mm slit length on the Star'Ex GEN2 to get a spectrum of the Orion Nebula (M42)?\u003c\/h3\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion-A\"\u003e\n\u003cp\u003eYes. The long \u003cstrong\u003e4mm slit length\u003c\/strong\u003e is specifically designed for capturing spectra of objects with large angular sizes, such as the Orion Nebula (M42) or comets. This allows you to study how the spectral characteristics change across different regions of the nebula in a single exposure.\u003c\/p\u003e\n\u003c\/div\u003e\n\u003c\/li\u003e\n\u003cli\u003e\n\u003ctable class=\"DAV-specifications\"\u003e\n\u003ctbody\u003e\n\u003ctr\u003e\n\u003ctd\u003eProduct\u003c\/td\u003e\n\u003ctd\u003e4-Position Reflective Slit (GEN2)\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eSlit Widths\u003c\/td\u003e\n\u003ctd\u003e14 µm, 20 µm, 26 µm, 32 µm\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eCentral Pinhole Diameter\u003c\/td\u003e\n\u003ctd\u003e25 µm\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eSlit Length\u003c\/td\u003e\n\u003ctd\u003e4 mm\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eSubstrate Material\u003c\/td\u003e\n\u003ctd\u003eFused Silica (Synthetic Quartz)\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eSubstrate Dimensions\u003c\/td\u003e\n\u003ctd\u003e16 mm x 16 mm\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eSubstrate Thickness\u003c\/td\u003e\n\u003ctd\u003e2 mm\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eCoatings\u003c\/td\u003e\n\u003ctd\u003eAnti-reflective (one side), Opaque Chromium (slit side)\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eCompatibility\u003c\/td\u003e\n\u003ctd\u003eStar’Ex Spectrographs, custom instruments\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003c\/tbody\u003e\n\u003c\/table\u003e\n\u003c\/li\u003e\n\u003cli\u003e\n\u003cul class=\"DAV-grid\"\u003e\n\u003cli class=\"DAV-grid-item\"\u003e\n\u003cdiv\u003e\n\u003cp class=\"DAV-item-title\"\u003eStar’Ex GEN2 4-Position Slit\u003c\/p\u003e\n\u003cp class=\"DAV-item-subtitle\"\u003e× 1\u003c\/p\u003e\n\u003c\/div\u003e\n\u003c\/li\u003e\n\u003c\/ul\u003e\n\u003c\/li\u003e\n\n\u003cli\u003e\n\u003ca href=\"https:\/\/davidastro.com\/pages\/shelyak-warranty-policy\" rel=\"noopener\" target=\"_blank\"\u003eShelyak 1-Year Warranty\u003c\/a\u003e\n\u003c\/li\u003e\n\u003c\/ul\u003e","brand":"Shelyak","offers":[{"title":"Default Title","offer_id":52943055159581,"sku":"SHK-SE0288","price":127.0,"currency_code":"CAD","in_stock":true}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0753\/5280\/1565\/files\/Shelyak-Star-Ex-14-20-26-32-m-slit-25-m-hole-GEN2-1_4f93cd48-7203-4178-9c33-d324015bfd63.jpg?v=1789616548"},{"product_id":"shelyak-se0289","title":"Shelyak Sol’Ex \/ SUNSCAN 2-position slit 7 – 10 µm (GEN2)","description":"\u003cul class=\"DAV-feature-list\"\u003e\n\u003cli\u003eDual Slit Widths: 7µm and 10µm\u003c\/li\u003e\n\u003cli\u003eSubstrate Dimensions: 12 x 8 x 2 mm\u003c\/li\u003e\n\u003cli\u003eMaterial: Heat-Resistant Eagle XG Glass\u003c\/li\u003e\n\u003cli\u003eWavelength Range: 350 nm to 1000 nm\u003c\/li\u003e\n\u003cli\u003eCoating: Anti-Reflection\u003c\/li\u003e\n\u003cli\u003eFor Sol'Ex \u0026amp; SUNSCAN Spectroheliographs\u003c\/li\u003e\n\u003c\/ul\u003e\n\u003c!-- more --\u003e\n\u003cul class=\"tabs\"\u003e\n\u003cli class=\"active\"\u003eDescription\u003c\/li\u003e\n\u003cli\u003eFAQ\u003c\/li\u003e\n\u003cli\u003eSpecifications\u003c\/li\u003e\n\u003cli\u003eIn the Box\u003c\/li\u003e\n\u003cli\u003eWarranty\u003c\/li\u003e\n\u003c\/ul\u003e\n\u003cul class=\"tabs-content\"\u003e\n\u003cli class=\"active\"\u003e\n\u003cdiv\u003e\n\u003cdiv class=\"DAV-bg-light\"\u003e\n\u003cdiv class=\"DAV-section-center\"\u003e\n\u003ch2\u003eSol’Ex \/ SUNSCAN 2-position slit 7 – 10 µm (GEN2)\u003c\/h2\u003e\n\u003cp\u003eThe Sol’Ex \/ SUNSCAN GEN2 2-position slit features two parallel slits, 7µm and 10µm wide, on a single 12 x 8 mm glass blade. This second-generation design uses a 2 mm thick, heat-resistant Eagle XG substrate with an anti-reflection coating effective from 350 to 1000 nm. The narrower 7µm slit is specifically included for high-precision applications, such as solar magnetic field measurement, giving spectroheliograph builders a critical optical component.\u003c\/p\u003e\n\u003c\/div\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-bg-light\"\u003e\n\u003cdiv class=\"DAV-section\"\u003e\n\u003ch3\u003eDual 7µm and 10µm Slits for High-Resolution Solar Work\u003c\/h3\u003e\n\u003cp\u003eThis GEN2 component incorporates two selectable slits on a single substrate, allowing you to switch between different resolutions without changing parts. The 10µm slit is excellent for general solar spectroscopy, while the finer 7µm slit enables more demanding, high-precision studies where greater spectral resolution is required. This narrower aperture is particularly effective for projects like measuring solar magnetic fields via the Zeeman effect.\u003c\/p\u003e\n\u003c\/div\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-bg-light\"\u003e\n\u003cdiv class=\"DAV-section\"\u003e\n\u003ch3\u003e2mm Thick Eagle XG Substrate with 350-1000nm AR Coating\u003c\/h3\u003e\n\u003cp\u003eThe slit is fabricated on a specialized Eagle XG glass substrate, chosen for its thermal resistance and excellent transmission across a wide 350 to 1000 nm wavelength range. The 2 mm thickness makes the 12 x 8 mm blade robust and easy to handle. It also simplifies cleaning, as both sides can be safely wiped with absorbent cotton and water. The face opposite the slit is anti-reflection coated to maximize light throughput and minimize internal reflections.\u003c\/p\u003e\n\u003c\/div\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-bg-light\"\u003e\n\u003cdiv class=\"DAV-section\"\u003e\n\u003ch3\u003eDesigned for Sol’Ex, SUNSCAN, and Custom Spectrographs\u003c\/h3\u003e\n\u003cp\u003eWhile designed as a direct upgrade for the Sol’Ex and SUNSCAN spectroheliographs, this 2-position slit is also available for your own custom instrument projects. Please note that the slit is delivered without a holder. For Sol’Ex users, the 3D printing files and instructions for the support are available in the project documentation; for custom builds, you will need to design your own mounting solution.\u003c\/p\u003e\n\u003c\/div\u003e\n\u003c\/div\u003e\n\u003c\/div\u003e\n\u003c\/li\u003e\n\u003cli\u003e\n\u003cdiv class=\"DAV-accordion\"\u003e\n\u003ch3 class=\"DAV-accordion-Q\"\u003eWhat is the advantage of the GEN2 2-position slit for a Sol'Ex instrument?\u003c\/h3\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion-A\"\u003e\n\u003cp\u003eThe primary advantage is having two slit widths on a single component. You can use the \u003cstrong\u003e10µm slit\u003c\/strong\u003e for brighter, general-purpose solar viewing and the \u003cstrong\u003e7µm slit\u003c\/strong\u003e for high-resolution studies, such as measuring magnetic fields, without needing to disassemble the instrument to swap slits.\u003c\/p\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion\"\u003e\n\u003ch3 class=\"DAV-accordion-Q\"\u003eDo I need to buy a separate holder for this Sol’Ex \/ SUNSCAN slit?\u003c\/h3\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion-A\"\u003e\n\u003cp\u003eYes, the slit is delivered without its 3D-printed support. You must fabricate the holder yourself. For \u003cstrong\u003eSol'Ex and SUNSCAN users\u003c\/strong\u003e, the necessary files and instructions are provided in the official instrument documentation. If you are using this for a custom project, you must design and create your own support.\u003c\/p\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion\"\u003e\n\u003ch3 class=\"DAV-accordion-Q\"\u003eHow do I clean the GEN2 2-position slit?\u003c\/h3\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion-A\"\u003e\n\u003cp\u003eThe 2 mm thick glass substrate is relatively robust. You can safely clean both sides using a soft, absorbent cotton ball lightly moistened with water. This helps remove dust and residue without damaging the slit or the anti-reflection coating.\u003c\/p\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion\"\u003e\n\u003ch3 class=\"DAV-accordion-Q\"\u003eWhich slit on the Sol'Ex \/ SUNSCAN GEN2 slit is better for measuring the Zeeman effect?\u003c\/h3\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion-A\"\u003e\n\u003cp\u003eThe narrower \u003cstrong\u003e7µm slit\u003c\/strong\u003e is designed for high-precision applications like measuring the Zeeman splitting of spectral lines. This requires higher spectral resolution to resolve the small wavelength shifts caused by solar magnetic fields, making the 7µm slit the ideal choice for this type of scientific work.\u003c\/p\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion\"\u003e\n\u003ch3 class=\"DAV-accordion-Q\"\u003eCan I use this slit to study the Fraunhofer lines in the solar spectrum with my custom spectrograph?\u003c\/h3\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion-A\"\u003e\n\u003cp\u003eAbsolutely. The slit's excellent transmission from \u003cstrong\u003e350 to 1000 nm\u003c\/strong\u003e covers the entire visible spectrum and beyond, making it perfect for studying the solar continuum and its many Fraunhofer absorption lines. You would need to design a compatible holder for your specific instrument.\u003c\/p\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion\"\u003e\n\u003ch3 class=\"DAV-accordion-Q\"\u003eIs the GEN2 2-position slit compatible with older Sol'Ex and SUNSCAN builds?\u003c\/h3\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion-A\"\u003e\n\u003cp\u003eYes, this is a compatible upgrade for existing Sol'Ex and SUNSCAN instruments. However, you will need to print the corresponding GEN2 holder for it, as the mount design may have changed from earlier versions. Always refer to the latest project documentation for the correct 3D printing files.\u003c\/p\u003e\n\u003c\/div\u003e\n\u003c\/li\u003e\n\u003cli\u003e\n\u003ctable class=\"DAV-specifications\"\u003e\n\u003ctbody\u003e\n\u003ctr\u003e\n\u003ctd\u003eProduct\u003c\/td\u003e\n\u003ctd\u003e2-Position Slit GEN2\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eSlit Widths\u003c\/td\u003e\n\u003ctd\u003e7 µm and 10 µm\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eCompatibility\u003c\/td\u003e\n\u003ctd\u003eSol’Ex, SUNSCAN, Custom Projects\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eSubstrate Material\u003c\/td\u003e\n\u003ctd\u003eEagle XG Glass\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eSubstrate Dimensions\u003c\/td\u003e\n\u003ctd\u003e12 x 8 mm\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eSubstrate Thickness\u003c\/td\u003e\n\u003ctd\u003e2 mm\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eEffective Wavelength Range\u003c\/td\u003e\n\u003ctd\u003e350 - 1000 nm\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eCoating\u003c\/td\u003e\n\u003ctd\u003eAnti-Reflection (one side)\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eHolder\u003c\/td\u003e\n\u003ctd\u003eNot included (requires 3D printing)\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003c\/tbody\u003e\n\u003c\/table\u003e\n\u003c\/li\u003e\n\u003cli\u003e\n\u003cul class=\"DAV-grid\"\u003e\n\u003cli class=\"DAV-grid-item\"\u003e\n\u003cdiv\u003e\n\u003cp class=\"DAV-item-title\"\u003eSol’Ex \/ SUNSCAN 2-position slit 7 – 10 µm (GEN2)\u003c\/p\u003e\n\u003cp class=\"DAV-item-subtitle\"\u003e× 1\u003c\/p\u003e\n\u003c\/div\u003e\n\u003c\/li\u003e\n\u003c\/ul\u003e\n\u003c\/li\u003e\n\u003cli\u003e\n\u003ca href=\"https:\/\/davidastro.com\/pages\/shelyak-warranty-policy\" rel=\"noopener\" target=\"_blank\"\u003eShelyak 1-Year Warranty\u003c\/a\u003e\n\u003c\/li\u003e\n\u003c\/ul\u003e","brand":"Shelyak","offers":[{"title":"Default Title","offer_id":52943055454493,"sku":"SHK-SE0289","price":106.0,"currency_code":"CAD","in_stock":true}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0753\/5280\/1565\/files\/Shelyak-Sol-Ex-SUNSCAN-2-position-slit-7-10-m-GEN2-1_c2318036-6b1a-4b6a-913b-a8f03015d4d5.jpg?v=1789616557"}],"url":"https:\/\/davidastro.com\/en-us\/collections\/gratings-and-slits.oembed","provider":"David Astro","version":"1.0","type":"link"}