{"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","url":"https:\/\/davidastro.com\/fr\/products\/shelyak-se0122","provider":"David Astro","version":"1.0","type":"link"}