{"product_id":"refurbished-ultra-cat-131","title":"[Refurbished] Ultra-Cat 131","description":"\u003cp data-start=\"97\" data-end=\"497\"\u003e\u003cstrong data-start=\"97\" data-end=\"133\"\u003eThe William Optics Ultra-Cat 131\u003c\/strong\u003e 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 data-start=\"499\" data-end=\"887\"\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\u003cbr\u003e\u003c\/strong\u003eEliminates field curvature, providing sharp, flat-field images without requiring additional flatteners.\u003c\/p\u003e\n\u003cp\u003e\u003cstrong\u003e60mm Superior Image Circle\u003cbr\u003e\u003c\/strong\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\u003cbr\u003e\u003c\/strong\u003eOffers exceptional light-gathering capability for vibrant deep-sky photography.\u003c\/p\u003e\n\u003cp\u003e\u003cstrong\u003eWIFD (William’s Internal Focuser Design)\u003cbr\u003e\u003c\/strong\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\u003cbr\u003e\u003c\/strong\u003eMinimizes thermal expansion and contraction, maintaining perfect optical alignment in any environment.\u003c\/p\u003e\n\u003cp\u003e\u003cstrong\u003eSensor Tilt Xterminator\u003cbr\u003e\u003c\/strong\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\u003cbr\u003e\u003c\/strong\u003eSimplifies focusing for pinpoint precision, a feature that sets it apart from competitors.\u003c\/p\u003e\n\u003cp\u003e\u003cstrong\u003ePatented Handle Bar Design\u003cbr\u003e\u003c\/strong\u003eCombines ergonomic usability with enhanced portability.\u003c\/p\u003e\n\u003cp\u003e\u003cstrong\u003ePersonalized Laser Engraving\u003cbr\u003e\u003c\/strong\u003eFree customization for direct purchases, adding a personal touch to your telescope.\u003c\/p\u003e","brand":"William Optics","offers":[{"title":"Ultra","offer_id":50605642514649,"sku":"T-C-131BR-Refurbished","price":5198.0,"currency_code":"USD","in_stock":true}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0675\/5752\/3673\/files\/UC-131-pers-1.jpg?v=1770104248","url":"https:\/\/williamoptics.com\/products\/refurbished-ultra-cat-131","provider":"William Optics","version":"1.0","type":"link"}