{"product_id":"william-optics-ultra-cat-56","title":"William Optics Ultra-Cat 56 (T-C-56BR)","description":"\u003ch1 data-start=\"237\" data-end=\"464\"\u003eWilliam Optics Ultra-Cat 56\u003c\/h1\u003e\n\u003cp data-start=\"237\" data-end=\"464\"\u003eThe \u003cstrong data-start=\"241\" data-end=\"257\"\u003eUltra-Cat 56\u003c\/strong\u003e is a high-performance \u003cstrong data-start=\"280\" data-end=\"311\"\u003e56mm apochromatic refractor\u003c\/strong\u003e, engineered for astrophotographers who demand exceptional portability without sacrificing optical precision, color accuracy, and wide-field performance.\u003c\/p\u003e\n\u003cp data-start=\"466\" data-end=\"956\"\u003eFeaturing a \u003cstrong data-start=\"478\" data-end=\"523\"\u003e5-element advanced Petzval optical design\u003c\/strong\u003e with \u003cstrong data-start=\"529\" data-end=\"561\"\u003esuper ED and lanthanum glass\u003c\/strong\u003e, paired with a fast \u003cstrong data-start=\"582\" data-end=\"603\"\u003ef\/4.8 focal ratio\u003c\/strong\u003e, the Ultra-Cat 56 delivers \u003cstrong data-start=\"631\" data-end=\"669\"\u003erazor-sharp, perfectly flat images\u003c\/strong\u003e across a \u003cstrong data-start=\"679\" data-end=\"700\"\u003e50mm image circle\u003c\/strong\u003e. With a \u003cstrong data-start=\"709\" data-end=\"731\"\u003e269mm focal length\u003c\/strong\u003e, it is optimized for \u003cstrong data-start=\"753\" data-end=\"792\"\u003eFull Frame, APS-C, and M4\/3 sensors\u003c\/strong\u003e, and remains fully compatible with \u003cstrong data-start=\"828\" data-end=\"853\"\u003eMedium Format cameras\u003c\/strong\u003e, making it an ideal ultra-wide-field imaging platform for deep-sky and large-scale nebula photography.\u003c\/p\u003e\n\u003ch2 dir=\"ltr\"\u003eKey Features:\u003cb\u003e\u003c\/b\u003e\n\u003c\/h2\u003e\n\u003cp dir=\"ltr\" role=\"presentation\"\u003e\u003cstrong\u003eAdvanced 5-Element Petzval Optics\u003cbr\u003e\u003c\/strong\u003e\u003cspan\u003eEliminates field curvature, ensuring sharp, edge-to-edge stars without additional flatteners.\u003c\/span\u003e\u003c\/p\u003e\n\u003cp dir=\"ltr\" role=\"presentation\"\u003e\u003cstrong\u003e50mm Large Image Circle\u003c\/strong\u003e\u003cspan\u003e\u003cbr\u003e\u003c\/span\u003e\u003cspan\u003eFully supports Full Frame cameras, APS-C and M4\/3 sensors for optimal performance. Compatible with Medium Format.\u003c\/span\u003e\u003c\/p\u003e\n\u003cp dir=\"ltr\" role=\"presentation\"\u003e\u003cstrong\u003eFast f\/4.8 Optics\u003c\/strong\u003e\u003cspan\u003e\u003cbr\u003e\u003c\/span\u003e\u003cspan\u003eSuperior light-gathering capability, enabling deep-sky imaging with shorter exposure times.\u003c\/span\u003e\u003c\/p\u003e\n\u003cp dir=\"ltr\" role=\"presentation\"\u003e\u003cstrong\u003eWIFD (William Optics Internal Focuser Design)\u003cbr\u003e\u003c\/strong\u003e\u003cspan\u003ePatented internal rack-and-pinion focuser ensures stable and precise focusing.\u003cbr\u003e\u003c\/span\u003e\u003cspan\u003eNo vignetting or balance issues — ideal for astrophotography.\u003cbr\u003e\u003c\/span\u003e\u003cspan\u003eCompatible with EAF (Electronic Automatic Focuser) for precision focus control.\u003c\/span\u003e\u003c\/p\u003e\n\u003cp dir=\"ltr\" role=\"presentation\"\u003e\u003cstrong\u003eSensor Tilt Xterminator (STX) \u0026amp; Rotator\u003c\/strong\u003e\u003cspan\u003e\u003cbr\u003e\u003c\/span\u003e\u003cspan\u003eIntegrated tilt adjuster eliminates sensor misalignment, ensuring uniform image sharpness.\u003c\/span\u003e\u003c\/p\u003e\n\u003cp dir=\"ltr\" role=\"presentation\"\u003e\u003cstrong\u003eNo Flattener Required\u003c\/strong\u003e\u003cspan\u003e\u003cbr\u003e\u003c\/span\u003e\u003cspan\u003eThe optical design naturally corrects field curvature, simplifying setup.\u003c\/span\u003e\u003c\/p\u003e\n\u003cp dir=\"ltr\" role=\"presentation\"\u003e\u003cstrong\u003eAnti-Shrink Lens Cell Technology\u003c\/strong\u003e\u003cspan\u003e\u003cbr\u003e\u003c\/span\u003e\u003cspan\u003eReduces thermal expansion effects, maintaining perfect optical alignment in any climate.\u003c\/span\u003e\u003c\/p\u003e\n\u003cp dir=\"ltr\" role=\"presentation\"\u003e\u003cstrong\u003ePatented Bahtinov Mask for Focusing\u003c\/strong\u003e\u003cspan\u003e\u003cbr\u003e\u003c\/span\u003e\u003cspan\u003eBuilt-in focusing aid ensures pinpoint star sharpness with ease.\u003c\/span\u003e\u003c\/p\u003e\n\u003cp dir=\"ltr\" role=\"presentation\"\u003e\u003cstrong\u003ePremium Build \u0026amp; Ergonomic Design\u003cbr\u003e\u003c\/strong\u003e\u003cspan\u003eLightweight yet robust (4.31 kg \/ 9.5 lbs) construction\u003c\/span\u003e\u003cspan\u003e with a sleek anodized finish.\u003cbr\u003e\u003c\/span\u003e\u003cspan\u003ePatented handle bar design\u003c\/span\u003e\u003cspan\u003e for enhanced portability and ease of use.\u003c\/span\u003e\u003c\/p\u003e\n\u003cp\u003e\u003cstrong\u003eVersatile Camera Compatibility\u003c\/strong\u003e\u003cb id=\"docs-internal-guid-3d0f6d30-7fff-0dd9-1c91-b1df13dca75f\"\u003e\u003cspan\u003e\u003cbr\u003e\u003c\/span\u003e\u003c\/b\u003eSupports Canon EF, RF, Nikon F,Z, Sony E, Pentax K, MFT, and FUJI X mounts.\u003c\/p\u003e\n\u003cdiv style=\"text-align: start;\"\u003e\u003cimg src=\"https:\/\/cdn.shopify.com\/s\/files\/1\/0652\/6245\/2965\/files\/Diagram_UltraCat-56_SD_1024x1024.webp?v=1767390379\" alt=\"\" style=\"margin-bottom: 16px; float: none;\"\u003e\u003c\/div\u003e\n\u003cdiv style=\"text-align: start;\"\u003e\u003cimg src=\"https:\/\/cdn.shopify.com\/s\/files\/1\/0652\/6245\/2965\/files\/Diagram_UltraCat-56_LA_1024x1024.webp?v=1767390399\" alt=\"\" style=\"float: none;\"\u003e\u003c\/div\u003e\n\u003cp\u003e \u003c\/p\u003e\n\u003cp\u003e \u003c\/p\u003e\n\u003ch3\u003eTechnical Specifications\u003c\/h3\u003e\n\u003ctable\u003e\n\u003cthead\u003e\n\u003ctr\u003e\n\u003cth\u003e\u003cstrong\u003eLens Type\u003c\/strong\u003e\u003c\/th\u003e\n\u003cth\u003e5-Element Advanced Petzval\u003c\/th\u003e\n\u003c\/tr\u003e\n\u003c\/thead\u003e\n\u003ctbody\u003e\n\u003ctr\u003e\n\u003ctd\u003e\u003cstrong\u003eLens Elements\u003c\/strong\u003e\u003c\/td\u003e\n\u003ctd\u003eSuper ED Glass x2 ED Glass x1 Lanthanum Glass x1 X-Element x1\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003e\u003cstrong\u003eFocal Length\u003c\/strong\u003e\u003c\/td\u003e\n\u003ctd\u003e269 mm\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003e\u003cstrong\u003eDiameter\u003c\/strong\u003e\u003c\/td\u003e\n\u003ctd\u003e56 mm\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003e\u003cstrong\u003eFocal Ratio\u003c\/strong\u003e\u003c\/td\u003e\n\u003ctd\u003ef\/4.8\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003e\u003cstrong\u003eImage Circle\u003c\/strong\u003e\u003c\/td\u003e\n\u003ctd\u003e50 mm\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003e\u003cstrong\u003eFocuser\u003c\/strong\u003e\u003c\/td\u003e\n\u003ctd\u003eWIFD R\u0026amp;P Focuser Compatible with EAF\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003e\u003cstrong\u003eFocus Travel\u003c\/strong\u003e\u003c\/td\u003e\n\u003ctd\u003e0–30 mm\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003e\u003cstrong\u003eAdapter Included\u003c\/strong\u003e\u003c\/td\u003e\n\u003ctd\u003eSensor Tilt Xterminator Rotator M54, M48 Camera Adapters\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003e\u003cstrong\u003eOptional Flattener\u003c\/strong\u003e\u003c\/td\u003e\n\u003ctd\u003eNo Flattener Required\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003e\u003cstrong\u003eT-Mount Support\u003c\/strong\u003e\u003c\/td\u003e\n\u003ctd\u003eCanon EF, RF Nikon F, Z Sony E Pentax K MFT (M4\/3) FUJI X\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003e\u003cstrong\u003eCamera Format\u003c\/strong\u003e\u003c\/td\u003e\n\u003ctd\u003eFull Frame APS-C M4\/3\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003e\u003cstrong\u003eDovetail Type\u003c\/strong\u003e\u003c\/td\u003e\n\u003ctd\u003eVixen ↔ Arca-Swiss\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003e\u003cstrong\u003eTube Length\u003c\/strong\u003e\u003c\/td\u003e\n\u003ctd\u003e296.3 mm – 348.3 mm\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003e\u003cstrong\u003eOTA Weight\u003c\/strong\u003e\u003c\/td\u003e\n\u003ctd\u003e2.56 kg \/ 5.64 lbs\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003e\u003cstrong\u003eTotal Weight\u003c\/strong\u003e\u003c\/td\u003e\n\u003ctd\u003e3.21 kg \/ 7.08 lbs\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003c\/tbody\u003e\n\u003c\/table\u003e\n\u003cp\u003e \u003c\/p\u003e\n\u003ch3\u003eIn the Box\u003c\/h3\u003e\n\u003cul\u003e\n\u003cli\u003eMain tube\u003c\/li\u003e\n\u003cli\u003eBahtinov Cap\u003c\/li\u003e\n\u003cli\u003eM48, M54 Adapter with wrench\u003c\/li\u003e\n\u003cli\u003eDual Side Plate\u003c\/li\u003e\n\u003cli\u003eMounting Ring and Handle bar\u003c\/li\u003e\n\u003cli\u003eSoft Carry case\u003c\/li\u003e\n\u003cli\u003eAllen Key Set\u003c\/li\u003e\n\u003c\/ul\u003e\n\u003ch3\u003eWarranty \u0026amp; Manual\u003c\/h3\u003e\n\u003cp\u003e\u003ca rel=\"noopener\" href=\"https:\/\/istronomyplus.com\/pages\/william-optics-warranty?srsltid=AfmBOopOJhrnJJHCbIcAy4PqqyY3Z3eren5LqIaJQwywHgnuL-nCjtsn\" title=\"William Optics 2-year Warranty\" target=\"_blank\"\u003eWilliam Optics 2-year Warranty\u003c\/a\u003e\u003c\/p\u003e","brand":"William Optics","offers":[{"title":"Default Title","offer_id":48220037906661,"sku":"WO-T-C-56BR","price":1929.0,"currency_code":"CAD","in_stock":true}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0652\/6245\/2965\/files\/UC56-pers-1.webp?v=1767390792","url":"https:\/\/istronomyplus.com\/products\/william-optics-ultra-cat-56","provider":"Astronomy Plus – Telescopes \u0026 Astrophotography Canada","version":"1.0","type":"link"}