{"product_id":"william-optics-redcat-91-wifd-91mm-f-4-9-apochromatic-refractor-telescope-ota-only","title":"William Optics RedCat 91 WIFD 91mm f\/4.9 Apochromatic Refractor Telescope (OTA Only","description":"Featuring an image circle big enough for medium-format photography, the \u003cb\u003eRedCat 91 WIFD 91mm f\/4.9 Apochromatic Refractor Telescope\u003c\/b\u003e from \u003cb\u003eWilliam Optics\u003c\/b\u003e is a photo-only optical tube assembly built for making gorgeous deep-sky images. The RedCat 91 features a fully multicoated five-element lens with super ED, ED, and Lanthanum elements in a field-flattening Petzval design that delivers edge-to-edge sharpness and eliminates complex back-focus calculations. The William Optics Internal Focus Design does away with rear focusers that sag under heavy cameras and accessories; instead, a rigid and balanced 1:10 rack-and-pinion focuser in the middle of the OTA prevents tube tilt and resulting vignetting.","brand":"William Optics","offers":[{"title":"Default Title","offer_id":48007354450137,"sku":"WITC91","price":6595.0,"currency_code":"USD","in_stock":true}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0016\/5327\/6707\/files\/1748514192_IMG_2504169.jpg?v=1767554848","url":"https:\/\/www.aloinfousa.com\/sr\/products\/william-optics-redcat-91-wifd-91mm-f-4-9-apochromatic-refractor-telescope-ota-only","provider":"aloinfousa.com","version":"1.0","type":"link"}