{"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":738.0,"currency_code":"USD","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","url":"https:\/\/davidastro.com\/fr-us\/products\/shelyak-se0008","provider":"David Astro","version":"1.0","type":"link"}