{"product_id":"william-optics-ultra-cat-131-wfid-apo-petzval-ota-l-uc131","title":"William Optics Ultra-Cat 131 WFID APO Petzval OTA | L-UC131","description":"\u003cp\u003eThe William Optics Ultra-Cat 131 is the flagship of the Ultra-Cat series, representing the pinnacle of wide-field astrophotography performance. Built around a large-aperture 131mm apochromatic optical system and an advanced 5-element Petzval design, it delivers extraordinary light-gathering power, exceptional color correction, and razor-sharp stars across an expansive, flat image circle.\u003c\/p\u003e\n\u003cp\u003eDesigned for serious astrophotographers and observatories alike, the Ultra-Cat 131 combines a fast focal ratio with uncompromising optical precision, enabling stunning deep-sky detail, rich contrast, and immersive wide-field compositions. Its premium mechanical construction, thermal stability, and flagship-level engineering set a new benchmark for large-format astrophotography systems.\u003c\/p\u003e\n\u003ch3\u003eKEY FEATURES:\u003c\/h3\u003e\n\u003cp\u003e\u003cstrong\u003eAdvanced 5-Element Petzval Design\u003c\/strong\u003e\u003cbr\u003eEliminates field curvature, providing sharp, flat-field images without requiring additional flatteners.\u003c\/p\u003e\n\u003cp\u003e\u003cstrong\u003e60mm Superior Image Circle\u003c\/strong\u003e\u003cbr\u003eFully supports full-frame and medium-format cameras for wide-field and detailed astrophotography, outperforming standard 106mm telescopes.\u003c\/p\u003e\n\u003cp\u003e\u003cstrong\u003eF\/4.9 Fast Optics\u003c\/strong\u003e\u003cbr\u003eOffers exceptional light-gathering capability for vibrant deep-sky photography.\u003c\/p\u003e\n\u003cp\u003e\u003cstrong\u003eWIFD (William’s Internal Focuser Design)\u003c\/strong\u003e\u003cbr\u003ePatented internal focuser ensures precise, stable, and hassle-free imaging, avoiding balance issues and eliminating vignetting.\u003c\/p\u003e\n\u003cp\u003e\u003cstrong\u003eAnti-Shrink Lens Cell Technology\u003c\/strong\u003e\u003cbr\u003eMinimizes thermal expansion and contraction, maintaining perfect optical alignment in any environment.\u003c\/p\u003e\n\u003cp\u003e\u003cstrong\u003eSensor Tilt Corrector\u003c\/strong\u003e\u003cbr\u003eIntegrated and patented design eliminates distortion, optimizing sharpness and detail for professional-level results.\u003c\/p\u003e\n\u003cp\u003e\u003cstrong\u003eBuilt-In Patented Bahtinov Mask\u003c\/strong\u003e\u003cbr\u003eSimplifies focusing for pinpoint precision, a feature that sets it apart from competitors.\u003c\/p\u003e\n\u003cp\u003e\u003cstrong\u003ePatented Handle Bar Design\u003c\/strong\u003e\u003cbr\u003eCombines ergonomic usability with enhanced portability.\u003c\/p\u003e\n\u003ch2\u003eSpecifications\u003c\/h2\u003e\n\u003ctable style=\"width: 100%; height: 352.688px;\"\u003e\n\u003ctbody\u003e\n\u003ctr style=\"height: 19.5938px;\"\u003e\n\u003ctd style=\"width: 20.8196%; height: 19.5938px;\"\u003e Lens Type\u003c\/td\u003e\n\u003ctd style=\"width: 75.9151%; height: 19.5938px;\"\u003e5-Element Advanced Petzval\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr style=\"height: 39.1875px;\"\u003e\n\u003ctd style=\"width: 20.8196%; height: 39.1875px;\"\u003eLens Elements\u003c\/td\u003e\n\u003ctd style=\"width: 75.9151%; height: 39.1875px;\"\u003eSuper ED Glass x2 ED Glass x1 Lanthanum Glass x1 X-Element x1\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr style=\"height: 19.5938px;\"\u003e\n\u003ctd style=\"width: 20.8196%; height: 19.5938px;\"\u003eFocal Length\u003c\/td\u003e\n\u003ctd style=\"width: 75.9151%; height: 19.5938px;\"\u003e648 mm\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr style=\"height: 19.5938px;\"\u003e\n\u003ctd style=\"width: 20.8196%; height: 19.5938px;\"\u003eDiameter\u003c\/td\u003e\n\u003ctd style=\"width: 75.9151%; height: 19.5938px;\"\u003e131 mm\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr style=\"height: 19.5938px;\"\u003e\n\u003ctd style=\"width: 20.8196%; height: 19.5938px;\"\u003eFocal Ratio\u003c\/td\u003e\n\u003ctd style=\"width: 75.9151%; height: 19.5938px;\"\u003ef\/4.9\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr style=\"height: 19.5938px;\"\u003e\n\u003ctd style=\"width: 20.8196%; height: 19.5938px;\"\u003eImage Circle\u003c\/td\u003e\n\u003ctd style=\"width: 75.9151%; height: 19.5938px;\"\u003e60 mm\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr style=\"height: 19.5938px;\"\u003e\n\u003ctd style=\"width: 20.8196%; height: 19.5938px;\"\u003eFocuser\u003c\/td\u003e\n\u003ctd style=\"width: 75.9151%; height: 19.5938px;\"\u003eWIFD R\u0026amp;P Focuser Compatible with EAF\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr style=\"height: 39.1875px;\"\u003e\n\u003ctd style=\"width: 20.8196%; height: 39.1875px;\"\u003eFocuser Travel\u003c\/td\u003e\n\u003ctd style=\"width: 75.9151%; height: 39.1875px;\"\u003e\n\u003cbr\u003e0-20 mm\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr style=\"height: 39.1875px;\"\u003e\n\u003ctd style=\"width: 20.8196%; height: 39.1875px;\"\u003eAdapter Included\u003c\/td\u003e\n\u003ctd style=\"width: 75.9151%; height: 39.1875px;\"\u003eSensor Tilt Xterminator Rotator M68, M54, M48 Camera Adapters\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr style=\"height: 39.1875px;\"\u003e\n\u003ctd style=\"width: 20.8196%; height: 39.1875px;\"\u003eOptional Flattener\u003cbr\u003e\n\u003c\/td\u003e\n\u003ctd style=\"width: 75.9151%; height: 39.1875px;\"\u003eNo Flattener Required\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr style=\"height: 39.1875px;\"\u003e\n\u003ctd style=\"width: 20.8196%; height: 39.1875px;\"\u003eT-Mount Support\u003c\/td\u003e\n\u003ctd style=\"width: 75.9151%; height: 39.1875px;\"\u003eCanon EF, RF Nikon F, Z Sony E Pentax K MFT (M4\/3) FUJI X\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr style=\"height: 19.5938px;\"\u003e\n\u003ctd style=\"width: 20.8196%; height: 19.5938px;\"\u003eCamera Format\u003c\/td\u003e\n\u003ctd style=\"width: 75.9151%; height: 19.5938px;\"\u003eMedium Format Full Frame APS-C M4\/3\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr style=\"height: 19.5938px;\"\u003e\n\u003ctd style=\"width: 20.8196%; height: 19.5938px;\"\u003eDovetail Type\u003c\/td\u003e\n\u003ctd style=\"width: 75.9151%; height: 19.5938px;\"\u003eLosmandy\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd style=\"width: 20.8196%;\"\u003eTube Length\u003c\/td\u003e\n\u003ctd style=\"width: 75.9151%;\"\u003e650 mm - 785.5 mm\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd style=\"width: 20.8196%;\"\u003eOTA Weight\u003c\/td\u003e\n\u003ctd style=\"width: 75.9151%;\"\u003e9.95 kg \/ 21.94 lbs\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003c\/tbody\u003e\n\u003c\/table\u003e\n\u003cp\u003e\u003cimg src=\"https:\/\/cdn.shopify.com\/s\/files\/1\/0610\/7702\/9116\/files\/Diagram_UltraCat-131_LA.webp?v=1772731795\" alt=\"\"\u003e\u003c\/p\u003e\n\u003cp\u003e\u003cimg src=\"https:\/\/cdn.shopify.com\/s\/files\/1\/0610\/7702\/9116\/files\/Diagram_UltraCat-131_SD.webp?v=1772731795\" alt=\"\"\u003e\u003c\/p\u003e","brand":"William Optics","offers":[{"title":"Default Title","offer_id":48823790403836,"sku":"L-UC131","price":7449.24,"currency_code":"CAD","in_stock":true}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0610\/7702\/9116\/files\/UC-131-pers-1.webp?v=1772731856","url":"https:\/\/all-startelescope.com\/products\/william-optics-ultra-cat-131-wfid-apo-petzval-ota-l-uc131","provider":"All-Star Telescope Canada","version":"1.0","type":"link"}