{"product_id":"william-optics-ultra-cat-56-wfid-apo-petzval-ota-l-uc56","title":"William Optics Ultra-Cat 56 WFID APO Petzval OTA (L-UC56)","description":"\u003cp\u003eIf you're looking for exceptional wide-field imaging performance in a compact astrograph, the William Optics Ultra-Cat 56 delivers in every way. Featuring an advanced 5-element Petzval optical design constructed from premium glass—including Super ED, ED, Lanthanum, and a proprietary X-Element—this telescope produces razor-sharp, well-corrected stars from center to edge. The naturally flat field eliminates the need for an external flattener or back-focus calculations, making camera setup simple and reliable. With a massive 50mm image circle, stars remain pinpoint across Full Frame sensors and beyond, with compatibility extending to Medium Format cameras. Designed specifically for astrophotography, the Ultra-Cat 56 is engineered to elevate both image quality and ease of use.\u003c\/p\u003e\n\u003cp\u003eWith a fast f\/4.8 focal ratio and a 269mm focal length, the Ultra-Cat 56 is optimized for capturing expansive deep-sky targets with shorter exposure times. The lightweight yet robust optical tube incorporates William Optics' patented Internal Focus Design (WIFD), providing smooth, precise, and vibration-free focusing without introducing vignetting or balance issues. The focuser is fully compatible with electronic autofocusers for hands-free precision. Integrated features such as the Sensor Tilt Xterminator (STX) and built-in rotator allow for fine tilt correction and effortless framing, ensuring uniform sharpness across the entire sensor. Combined with thoughtful engineering and premium build quality, the William Optics Ultra-Cat 56 stands out as a powerful, all-in-one imaging solution for serious astrophotographers.\u003c\/p\u003e\n\u003ch3\u003eKey Features\u003c\/h3\u003e\n\u003cul\u003e\n\u003cli\u003e\n\u003cstrong\u003eAdvanced 5-Element Petzval Optics:\u003c\/strong\u003e Eliminates field curvature, ensuring sharp, edge-to-edge stars without additional flatteners.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003e50mm Large Image Circle:\u003c\/strong\u003e Fully supports Full Frame cameras, APS-C and M4\/3 sensors for optimal performance. Compatible with Medium Format.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eFast f\/4.8 Optics:\u003c\/strong\u003e Superior light-gathering capability, enabling deep-sky imaging with shorter exposure times.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eWIFD (William's Internal Focuser Design):\u003c\/strong\u003e Patented internal rack-and-pinion focuser ensures stable and precise focusing. No vignetting or balance issues — ideal for astrophotography. Compatible with EAF (Electronic Automatic Focuser) for precision focus control.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eSensor Tilt Xterminator (STX) \u0026amp; Rotator:\u003c\/strong\u003e Integrated tilt adjuster eliminates sensor misalignment, ensuring uniform image sharpness.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eNo Flattener Required:\u003c\/strong\u003e The optical design naturally corrects field curvature, simplifying setup.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eAnti-Shrink Lens Cell Technology:\u003c\/strong\u003e Reduces thermal expansion effects, maintaining perfect optical alignment in any climate.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003ePatented Bahtinov Mask for Focusing:\u003c\/strong\u003e Built-in focusing aid ensures pinpoint star sharpness with ease.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003ePremium Build \u0026amp; Ergonomic Design:\u003c\/strong\u003e Lightweight yet robust (3.21 kg \/ 7.08 lbs) construction with a sleek anodized finish. Patented handle bar design for enhanced portability and ease of use.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eVersatile Camera Compatibility:\u003c\/strong\u003e Supports Canon EF, RF, Nikon F,Z, Sony E, Pentax K, MFT, and FUJI X mounts.\u003c\/li\u003e\n\u003c\/ul\u003e\n\u003ch3\u003eIncluded Sensor Tilt Xterminator (STX)\u003c\/h3\u003e\n\u003cp\u003eThe STX builds upon the foundation of traditional sensor tilt adjusters, offering a streamlined and intuitive design that eliminates the need for cumbersome disassembly. Unlike conventional systems that require camera removal for tilt correction, the STX allows adjustments to be made directly from the side of the assembly, significantly reducing setup time and enhancing ease of use.\u003c\/p\u003e\n\u003cp\u003eBy refining the original 4 pull-in and 8 push-out screw configuration into a more efficient 4 push-out and 4 locked screw system, the STX enables precise and controlled adjustments. Operating like a seesaw mechanism, the system allows for effortless corrections—simply loosen one screw and tighten the opposite diagonal screw to achieve fine tilt alignment. This ensures that astrophotographers can make on-the-fly refinements without disrupting their imaging workflow, maintaining pinpoint star performance across the entire frame.\u003c\/p\u003e\n\u003cp\u003e\u003cimg alt=\"\" src=\"https:\/\/cdn.shopify.com\/s\/files\/1\/0610\/7702\/9116\/files\/UC-STX.png?v=1742865706\"\u003e\u003c\/p\u003e\n\u003ch2\u003eSpecifications\u003c\/h2\u003e\n\u003ctable\u003e\n\u003ctbody\u003e\n\u003ctr\u003e\n\u003ctd\u003eDesign:\u003c\/td\u003e\n\u003ctd\u003e5-Element Advanced Petzval\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eLens Elements:\u003c\/td\u003e\n\u003ctd\u003e2x Super ED Glass\u003cbr\u003e1x ED Glass\u003cbr\u003e1x Lanthanum Glass\u003cbr\u003e1x X-Element\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eFocal Length:\u003c\/td\u003e\n\u003ctd\u003e269mm\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eDiameter:\u003c\/td\u003e\n\u003ctd\u003e56mm\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eAperture:\u003c\/td\u003e\n\u003ctd\u003ef\/4.8\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eFocuser:\u003c\/td\u003e\n\u003ctd\u003eWIFD (WilliamOptics Internal Focus Design)\u003cbr\u003e\u003cem\u003eNote: Compatible with EAF\u003c\/em\u003e\n\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eImage Circle:\u003c\/td\u003e\n\u003ctd\u003e50mm \u0026gt;Full Frame\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eTube Length:\u003c\/td\u003e\n\u003ctd\u003e296.3mm-349.3mm\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eTube Weight:\u003c\/td\u003e\n\u003ctd\u003e2.56kg \/ 5.64lbs\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eTotal Weight:\u003c\/td\u003e\n\u003ctd\u003e3.21kg \/ 7.08lbs\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eAdapters Included:\u003c\/td\u003e\n\u003ctd\u003eSensor Tilt Xterminator\u003cbr\u003eRotator\u003cbr\u003eM54\/M48 Camera Adapters\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eT-Mounts Supported:\u003c\/td\u003e\n\u003ctd\u003eCanon EF\/RF\u003cbr\u003eNikon F\/Z\u003cbr\u003eSony E\u003cbr\u003ePentax K\u003cbr\u003eMFT (M4\/3)\u003cbr\u003eFUJI X\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eCamera Formats Supported:\u003c\/td\u003e\n\u003ctd\u003eMedium Format (Compatible)\u003cbr\u003eFull Frame (Recommended)\u003cbr\u003eAPS-C\u003cbr\u003eM4\/3\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003c\/tbody\u003e\n\u003c\/table\u003e\n\u003cp\u003e\u003cstrong\u003eSpot Diagram\u003c\/strong\u003e\u003c\/p\u003e\n\u003cp\u003e\u003cimg alt=\"\" src=\"https:\/\/cdn.shopify.com\/s\/files\/1\/0610\/7702\/9116\/files\/L-UC56-SPOT.avif?v=1765946172\"\u003e\u003c\/p\u003e","brand":"William Optics","offers":[{"title":"Default Title","offer_id":48609183498492,"sku":"L-UC56","price":1929.24,"currency_code":"CAD","in_stock":true}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0610\/7702\/9116\/files\/UC56-pers-1.jpg?v=1765945426","url":"https:\/\/all-startelescope.com\/products\/william-optics-ultra-cat-56-wfid-apo-petzval-ota-l-uc56","provider":"All-Star Telescope Canada","version":"1.0","type":"link"}