{"product_id":"william-optics-apochromatic-refractor-ap-91-448-cat-91-series-wifd-ota","title":"William Optics Apochromatic refractor AP 91\/448 Cat 91 Series WIFD OTA","description":"\u003ch2\u003eDescription\u003c\/h2\u003e\n\u003cp\u003eThe AP 91\/448 optics are an impressive combination of compact dimensions, relatively low price and outstanding optical quality, and are aimed at all astrophotographers and nature photographers. At the heart of the optical design is the Petzval design consisting of 4 elements in 3 groups, using FPL53 and FPL51 glass. The result is a colour-pure, corrected image field with a diameter of over 55 millimetres – making it suitable for full-frame cameras! The fast aperture ratio of f\/4.9 allows for short exposure times.\u003c\/p\u003e\n\u003cp\u003eAn M48 and M54 thread is provided for connecting the camera. Two suitable adaptors are already included in the scope of delivery. Focusing is helical, i.e. by turning the easy-grip ring on the tube. This means that even heavy cameras are no problem. The telescope has a \"WIFD\" design, which stands for \"with internal focus design\". Focusing via the helical ring is therefore internal.\u003c\/p\u003e\n\u003cp\u003eThe included prism rail offers two connection options: for screwing with a photo thread, via Arca-Swiss mounting or for insertion into a prism clamp according to Losmandy standard. With these options, it should be no problem to attach the telescope to all common photo tripods, camera mounts or astronomical mounts.\u003c\/p\u003e\n\u003cp\u003eThe scope comes with a protective nylon carrying bag and a specially designed Bahtinov mask. This mask helps with focusing and is permanently integrated into the lens attachment.\u003c\/p\u003e\n\u003cp\u003eOptics such as the Cat 91 are ideal for photographers who are dedicated to the night sky, but also to animal photography. With the Cat 91, you not only get impressive optical performance, but you can also enjoy the durable and beautiful finish of William Optics.\u003c\/p\u003e\n\u003cp\u003eIt not only matters which telescope you buy but also where you buy it. Our additional services:\u003c\/p\u003e\n\u003cp\u003eWe are a leading telescope dealer and know the devices we sell. Our customer service team will gladly help you after your purchase if you have problems with assembly or operation.\u003c\/p\u003e\n\u003cp\u003eWe provide a copy of the 80-page Telescope ABC beginners handbook with every telescope.\u003c\/p\u003e\n\u003ch2\u003eSpecification\u003c\/h2\u003e\n\u003ctable style=\"width: 100%; border-collapse: collapse; line-height: 1.4;\"\u003e\n\u003ctbody\u003e\n\u003ctr\u003e\n\u003ctd colspan=\"2\" style=\"padding: 8px 4px 4px; font-weight: bold; font-size: 0.95em; border-bottom: 1px solid #333; color: #333;\"\u003eOptics\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr style=\"background: #f5f5f5;\"\u003e\n\u003ctd style=\"padding: 4px 6px; width: 50%; font-size: 0.9em; color: #333; border-bottom: 1px solid #e8e8e8;\"\u003eType\u003c\/td\u003e\n\u003ctd style=\"padding: 4px 6px; font-size: 0.9em; color: #333; border-bottom: 1px solid #e8e8e8;\"\u003eRefractor\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr style=\"background: #ffffff;\"\u003e\n\u003ctd style=\"padding: 4px 6px; width: 50%; font-size: 0.9em; color: #333; border-bottom: 1px solid #e8e8e8;\"\u003eType of build\u003c\/td\u003e\n\u003ctd style=\"padding: 4px 6px; font-size: 0.9em; color: #333; border-bottom: 1px solid #e8e8e8;\"\u003eApochromat\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr style=\"background: #f5f5f5;\"\u003e\n\u003ctd style=\"padding: 4px 6px; width: 50%; font-size: 0.9em; color: #333; border-bottom: 1px solid #e8e8e8;\"\u003eAperture (mm)\u003c\/td\u003e\n\u003ctd style=\"padding: 4px 6px; font-size: 0.9em; color: #333; border-bottom: 1px solid #e8e8e8;\"\u003e91\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr style=\"background: #ffffff;\"\u003e\n\u003ctd style=\"padding: 4px 6px; width: 50%; font-size: 0.9em; color: #333; border-bottom: 1px solid #e8e8e8;\"\u003eFocal length (mm)\u003c\/td\u003e\n\u003ctd style=\"padding: 4px 6px; font-size: 0.9em; color: #333; border-bottom: 1px solid #e8e8e8;\"\u003e448\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr style=\"background: #f5f5f5;\"\u003e\n\u003ctd style=\"padding: 4px 6px; width: 50%; font-size: 0.9em; color: #333; border-bottom: 1px solid #e8e8e8;\"\u003eAperture ratio (f\/)\u003c\/td\u003e\n\u003ctd style=\"padding: 4px 6px; font-size: 0.9em; color: #333; border-bottom: 1px solid #e8e8e8;\"\u003e4,9\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr style=\"background: #ffffff;\"\u003e\n\u003ctd style=\"padding: 4px 6px; width: 50%; font-size: 0.9em; color: #333; border-bottom: 1px solid #e8e8e8;\"\u003eResolving capacity\u003c\/td\u003e\n\u003ctd style=\"padding: 4px 6px; font-size: 0.9em; color: #333; border-bottom: 1px solid #e8e8e8;\"\u003e1,52\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr style=\"background: #f5f5f5;\"\u003e\n\u003ctd style=\"padding: 4px 6px; width: 50%; font-size: 0.9em; color: #333; border-bottom: 1px solid #e8e8e8;\"\u003eLimit value (mag)\u003c\/td\u003e\n\u003ctd style=\"padding: 4px 6px; font-size: 0.9em; color: #333; border-bottom: 1px solid #e8e8e8;\"\u003e12,3\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr style=\"background: #ffffff;\"\u003e\n\u003ctd style=\"padding: 4px 6px; width: 50%; font-size: 0.9em; color: #333; border-bottom: 1px solid #e8e8e8;\"\u003eLight gathering capacity\u003c\/td\u003e\n\u003ctd style=\"padding: 4px 6px; font-size: 0.9em; color: #333; border-bottom: 1px solid #e8e8e8;\"\u003e170\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr style=\"background: #f5f5f5;\"\u003e\n\u003ctd style=\"padding: 4px 6px; width: 50%; font-size: 0.9em; color: #333; border-bottom: 1px solid #e8e8e8;\"\u003eMax. useful magnification\u003c\/td\u003e\n\u003ctd style=\"padding: 4px 6px; font-size: 0.9em; color: #333; border-bottom: 1px solid #e8e8e8;\"\u003e182\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr style=\"background: #ffffff;\"\u003e\n\u003ctd style=\"padding: 4px 6px; width: 50%; font-size: 0.9em; color: #333; border-bottom: 1px solid #e8e8e8;\"\u003eTube weight (kg)\u003c\/td\u003e\n\u003ctd style=\"padding: 4px 6px; font-size: 0.9em; color: #333; border-bottom: 1px solid #e8e8e8;\"\u003e6,3\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr style=\"background: #f5f5f5;\"\u003e\n\u003ctd style=\"padding: 4px 6px; width: 50%; font-size: 0.9em; color: #333; border-bottom: 1px solid #e8e8e8;\"\u003eTube length (mm)\u003c\/td\u003e\n\u003ctd style=\"padding: 4px 6px; font-size: 0.9em; color: #333; border-bottom: 1px solid #e8e8e8;\"\u003e556\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr style=\"background: #ffffff;\"\u003e\n\u003ctd style=\"padding: 4px 6px; width: 50%; font-size: 0.9em; color: #333; border-bottom: 1px solid #e8e8e8;\"\u003eTube material\u003c\/td\u003e\n\u003ctd style=\"padding: 4px 6px; font-size: 0.9em; color: #333; border-bottom: 1px solid #e8e8e8;\"\u003eAluminium\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr style=\"background: #f5f5f5;\"\u003e\n\u003ctd style=\"padding: 4px 6px; width: 50%; font-size: 0.9em; color: #333; border-bottom: 1px solid #e8e8e8;\"\u003eCoating\u003c\/td\u003e\n\u003ctd style=\"padding: 4px 6px; font-size: 0.9em; color: #333; border-bottom: 1px solid #e8e8e8;\"\u003emultiple\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr style=\"background: #ffffff;\"\u003e\n\u003ctd style=\"padding: 4px 6px; width: 50%; font-size: 0.9em; color: #333; border-bottom: 1px solid #e8e8e8;\"\u003eTube construction\u003c\/td\u003e\n\u003ctd style=\"padding: 4px 6px; font-size: 0.9em; color: #333; border-bottom: 1px solid #e8e8e8;\"\u003eFull tube\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr style=\"background: #f5f5f5;\"\u003e\n\u003ctd style=\"padding: 4px 6px; width: 50%; font-size: 0.9em; color: #333; border-bottom: 1px solid #e8e8e8;\"\u003elens design\u003c\/td\u003e\n\u003ctd style=\"padding: 4px 6px; font-size: 0.9em; color: #333; border-bottom: 1px solid #e8e8e8;\"\u003eQuadruplet\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd colspan=\"2\" style=\"padding: 8px 4px 4px; font-weight: bold; font-size: 0.95em; border-bottom: 1px solid #333; color: #333;\"\u003eFocuser\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr style=\"background: #f5f5f5;\"\u003e\n\u003ctd style=\"padding: 4px 6px; width: 50%; font-size: 0.9em; color: #333; border-bottom: 1px solid #e8e8e8;\"\u003eTilting Adaptor\u003c\/td\u003e\n\u003ctd style=\"padding: 4px 6px; font-size: 0.9em; color: #333; border-bottom: 1px solid #e8e8e8;\"\u003eyes\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr style=\"background: #ffffff;\"\u003e\n\u003ctd style=\"padding: 4px 6px; width: 50%; font-size: 0.9em; color: #333; border-bottom: 1px solid #e8e8e8;\"\u003eType of build\u003c\/td\u003e\n\u003ctd style=\"padding: 4px 6px; font-size: 0.9em; color: #333; border-bottom: 1px solid #e8e8e8;\"\u003eHelical\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr style=\"background: #f5f5f5;\"\u003e\n\u003ctd style=\"padding: 4px 6px; width: 50%; font-size: 0.9em; color: #333; border-bottom: 1px solid #e8e8e8;\"\u003eConnecting threaded socket (camera-side)\u003c\/td\u003e\n\u003ctd style=\"padding: 4px 6px; font-size: 0.9em; color: #333; border-bottom: 1px solid #e8e8e8;\"\u003eM48 \/ M54\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr style=\"background: #ffffff;\"\u003e\n\u003ctd style=\"padding: 4px 6px; width: 50%; font-size: 0.9em; color: #333; border-bottom: 1px solid #e8e8e8;\"\u003eFree aperture (mm)\u003c\/td\u003e\n\u003ctd style=\"padding: 4px 6px; font-size: 0.9em; color: #333; border-bottom: 1px solid #e8e8e8;\"\u003e55\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr style=\"background: #f5f5f5;\"\u003e\n\u003ctd style=\"padding: 4px 6px; width: 50%; font-size: 0.9em; color: #333; border-bottom: 1px solid #e8e8e8;\"\u003eRotating\u003c\/td\u003e\n\u003ctd style=\"padding: 4px 6px; font-size: 0.9em; color: #333; border-bottom: 1px solid #e8e8e8;\"\u003eyes\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd colspan=\"2\" style=\"padding: 8px 4px 4px; font-weight: bold; font-size: 0.95em; border-bottom: 1px solid #333; color: #333;\"\u003eMount\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr style=\"background: #f5f5f5;\"\u003e\n\u003ctd style=\"padding: 4px 6px; width: 50%; font-size: 0.9em; color: #333; border-bottom: 1px solid #e8e8e8;\"\u003eType of build\u003c\/td\u003e\n\u003ctd style=\"padding: 4px 6px; font-size: 0.9em; color: #333; border-bottom: 1px solid #e8e8e8;\"\u003eOTA\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr style=\"background: #ffffff;\"\u003e\n\u003ctd style=\"padding: 4px 6px; width: 50%; font-size: 0.9em; color: #333; border-bottom: 1px solid #e8e8e8;\"\u003eMounting type\u003c\/td\u003e\n\u003ctd style=\"padding: 4px 6px; font-size: 0.9em; color: #333; border-bottom: 1px solid #e8e8e8;\"\u003eno mount\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd colspan=\"2\" style=\"padding: 8px 4px 4px; font-weight: bold; font-size: 0.95em; border-bottom: 1px solid #333; color: #333;\"\u003eIncluded accessories\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr style=\"background: #f5f5f5;\"\u003e\n\u003ctd style=\"padding: 4px 6px; width: 50%; font-size: 0.9em; color: #333; border-bottom: 1px solid #e8e8e8;\"\u003eDew Shield\u003c\/td\u003e\n\u003ctd style=\"padding: 4px 6px; font-size: 0.9em; color: #333; border-bottom: 1px solid #e8e8e8;\"\u003eyes\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr style=\"background: #ffffff;\"\u003e\n\u003ctd style=\"padding: 4px 6px; width: 50%; font-size: 0.9em; color: #333; border-bottom: 1px solid #e8e8e8;\"\u003eCarry case\u003c\/td\u003e\n\u003ctd style=\"padding: 4px 6px; font-size: 0.9em; color: #333; border-bottom: 1px solid #e8e8e8;\"\u003eyes\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr style=\"background: #f5f5f5;\"\u003e\n\u003ctd style=\"padding: 4px 6px; width: 50%; font-size: 0.9em; color: #333; border-bottom: 1px solid #e8e8e8;\"\u003eMiscellaneous\u003c\/td\u003e\n\u003ctd style=\"padding: 4px 6px; font-size: 0.9em; color: #333; border-bottom: 1px solid #e8e8e8;\"\u003eBahtinov focus mask\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr style=\"background: #ffffff;\"\u003e\n\u003ctd style=\"padding: 4px 6px; width: 50%; font-size: 0.9em; color: #333; border-bottom: 1px solid #e8e8e8;\"\u003ePrism rail\u003c\/td\u003e\n\u003ctd style=\"padding: 4px 6px; font-size: 0.9em; color: #333; border-bottom: 1px solid #e8e8e8;\"\u003eyes\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr style=\"background: #f5f5f5;\"\u003e\n\u003ctd style=\"padding: 4px 6px; width: 50%; font-size: 0.9em; color: #333; border-bottom: 1px solid #e8e8e8;\"\u003eThread for camera tripod\u003c\/td\u003e\n\u003ctd style=\"padding: 4px 6px; font-size: 0.9em; color: #333; border-bottom: 1px solid #e8e8e8;\"\u003eyes\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr style=\"background: #ffffff;\"\u003e\n\u003ctd style=\"padding: 4px 6px; width: 50%; font-size: 0.9em; color: #333; border-bottom: 1px solid #e8e8e8;\"\u003eCorrector\u003c\/td\u003e\n\u003ctd style=\"padding: 4px 6px; font-size: 0.9em; color: #333; border-bottom: 1px solid #e8e8e8;\"\u003eintegrated\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr style=\"background: #f5f5f5;\"\u003e\n\u003ctd style=\"padding: 4px 6px; width: 50%; font-size: 0.9em; color: #333; border-bottom: 1px solid #e8e8e8;\"\u003eEyepiece adaptor\u003c\/td\u003e\n\u003ctd style=\"padding: 4px 6px; font-size: 0.9em; color: #333; border-bottom: 1px solid #e8e8e8;\"\u003e1,25\" \u0026amp; 2\"\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd colspan=\"2\" style=\"padding: 8px 4px 4px; font-weight: bold; font-size: 0.95em; border-bottom: 1px solid #333; color: #333;\"\u003eGeneral\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr style=\"background: #f5f5f5;\"\u003e\n\u003ctd style=\"padding: 4px 6px; width: 50%; font-size: 0.9em; color: #333; border-bottom: 1px solid #e8e8e8;\"\u003eSeries\u003c\/td\u003e\n\u003ctd style=\"padding: 4px 6px; font-size: 0.9em; color: #333; border-bottom: 1px solid #e8e8e8;\"\u003eCat\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr style=\"background: #ffffff;\"\u003e\n\u003ctd style=\"padding: 4px 6px; width: 50%; font-size: 0.9em; color: #333; border-bottom: 1px solid #e8e8e8;\"\u003eColour\u003c\/td\u003e\n\u003ctd style=\"padding: 4px 6px; font-size: 0.9em; color: #333; border-bottom: 1px solid #e8e8e8;\"\u003ered, grey, black \u0026amp; red 30th anniversary\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd colspan=\"2\" style=\"padding: 8px 4px 4px; font-weight: bold; font-size: 0.95em; border-bottom: 1px solid #333; color: #333;\"\u003eArea of application\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr style=\"background: #f5f5f5;\"\u003e\n\u003ctd style=\"padding: 4px 6px; width: 50%; font-size: 0.9em; color: #333; border-bottom: 1px solid #e8e8e8;\"\u003eAstrophotography\u003c\/td\u003e\n\u003ctd style=\"padding: 4px 6px; font-size: 0.9em; color: #333; border-bottom: 1px solid #e8e8e8;\"\u003eyes (very good)\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr style=\"background: #ffffff;\"\u003e\n\u003ctd style=\"padding: 4px 6px; width: 50%; font-size: 0.9em; color: #333; border-bottom: 1px solid #e8e8e8;\"\u003eMoon \u0026amp; Planets\u003c\/td\u003e\n\u003ctd style=\"padding: 4px 6px; font-size: 0.9em; color: #333; border-bottom: 1px solid #e8e8e8;\"\u003eyes\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr style=\"background: #f5f5f5;\"\u003e\n\u003ctd style=\"padding: 4px 6px; width: 50%; font-size: 0.9em; color: #333; border-bottom: 1px solid #e8e8e8;\"\u003eNature Observation\u003c\/td\u003e\n\u003ctd style=\"padding: 4px 6px; font-size: 0.9em; color: #333; border-bottom: 1px solid #e8e8e8;\"\u003eyes\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr style=\"background: #ffffff;\"\u003e\n\u003ctd style=\"padding: 4px 6px; width: 50%; font-size: 0.9em; color: #333; border-bottom: 1px solid #e8e8e8;\"\u003eNebulae \u0026amp; galaxies\u003c\/td\u003e\n\u003ctd style=\"padding: 4px 6px; font-size: 0.9em; color: #333; border-bottom: 1px solid #e8e8e8;\"\u003eyes\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr style=\"background: #f5f5f5;\"\u003e\n\u003ctd style=\"padding: 4px 6px; width: 50%; font-size: 0.9em; color: #333; border-bottom: 1px solid #e8e8e8;\"\u003eSun\u003c\/td\u003e\n\u003ctd style=\"padding: 4px 6px; font-size: 0.9em; color: #333; border-bottom: 1px solid #e8e8e8;\"\u003eno (Only with appropriate Sun filter)\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd colspan=\"2\" style=\"padding: 8px 4px 4px; font-weight: bold; font-size: 0.95em; border-bottom: 1px solid #333; color: #333;\"\u003eRecommended for\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr style=\"background: #f5f5f5;\"\u003e\n\u003ctd style=\"padding: 4px 6px; width: 50%; font-size: 0.9em; color: #333; border-bottom: 1px solid #e8e8e8;\"\u003eBeginners\u003c\/td\u003e\n\u003ctd style=\"padding: 4px 6px; font-size: 0.9em; color: #333; border-bottom: 1px solid #e8e8e8;\"\u003eno\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr style=\"background: #ffffff;\"\u003e\n\u003ctd style=\"padding: 4px 6px; width: 50%; font-size: 0.9em; color: #333; border-bottom: 1px solid #e8e8e8;\"\u003eAdvanced\u003c\/td\u003e\n\u003ctd style=\"padding: 4px 6px; font-size: 0.9em; color: #333; border-bottom: 1px solid #e8e8e8;\"\u003eyes\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr style=\"background: #f5f5f5;\"\u003e\n\u003ctd style=\"padding: 4px 6px; width: 50%; font-size: 0.9em; color: #333; border-bottom: 1px solid #e8e8e8;\"\u003eObservatories\u003c\/td\u003e\n\u003ctd style=\"padding: 4px 6px; font-size: 0.9em; color: #333; border-bottom: 1px solid #e8e8e8;\"\u003eno\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003c\/tbody\u003e\n\u003c\/table\u003e","brand":"Nimax","offers":[{"title":"Red","offer_id":49313374863515,"sku":"85222","price":2699.0,"currency_code":"GBP","in_stock":true},{"title":"Gray","offer_id":49313374896283,"sku":"88166","price":2449.0,"currency_code":"GBP","in_stock":true},{"title":"Black","offer_id":49313374929051,"sku":"85223","price":3349.0,"currency_code":"GBP","in_stock":true},{"title":"Red 30th Special Edition","offer_id":49313392328859,"sku":"92935","price":2699.0,"currency_code":"GBP","in_stock":true}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0575\/5260\/1243\/files\/William-Optics-Apochromatic-refractor-AP-91-448-BlackCat-91-WIFD-OTA_1.jpg?v=1787046582","url":"https:\/\/astronoscope.com\/products\/william-optics-apochromatic-refractor-ap-91-448-cat-91-series-wifd-ota","provider":"Astronoscope","version":"1.0","type":"link"}