{"id":33717,"date":"2025-11-14T14:19:40","date_gmt":"2025-11-14T13:19:40","guid":{"rendered":"https:\/\/www.telescoop.nl\/?post_type=product&#038;p=33717"},"modified":"2026-03-04T17:18:00","modified_gmt":"2026-03-04T16:18:00","slug":"william-optics-blackcat-91-448-apo-wifd-ota","status":"publish","type":"product","link":"https:\/\/staging.telescoop.nl\/en\/william-optics-blackcat-91-448-apo-wifd-ota\/","title":{"rendered":"William Optics BlackCat 91\/448 APO WIFD OTA"},"content":{"rendered":"<h3 class=\"wp-block-heading\">Compact powerhouse for astrophotography<\/h3>\n\n\n\n<p class=\"wp-block-paragraph\">The <strong>William Optics AP 91\/448 91 BlackCat<\/strong> is perfect for astrophotographers and nature photographers.It combines compact size with impressive optical performance.The <strong>Petzval design with FPL53 and FPL51 glass<\/strong> delivers a color-clean, sharp image all the way to the edges of full-frame sensors.<\/p>\n\n\n\n<figure class=\"wp-block-gallery has-nested-images columns-default is-cropped wp-block-gallery-1 is-layout-flex wp-block-gallery-is-layout-flex\">\n<figure class=\"wp-block-image aligncenter size-large\"><img decoding=\"async\" data-id=\"33718\" src=\"https:\/\/staging.telescoop.nl\/wp-content\/uploads\/2025\/11\/William-Optics-AP-91-448-91-Apochromatische-refractor-BlackCat-WIFD-OTA-11.jpg\" alt=\"William Optics AP 91\/448 91 Apochromatic refractor BlackCat WIFD OTA oblique front view.\" class=\"wp-image-33718\" title=\"\"><\/figure>\n<\/figure>\n\n\n\n<h3 class=\"wp-block-heading\">Fast and clear<\/h3>\n\n\n\n<p class=\"wp-block-paragraph\">With a <strong>91 mm lens and f\/4.9<\/strong> capture a lot of light.That means short exposures and sharp details, even for faint stars.The <strong>field of view of more than 55 mm<\/strong> gives room for large sensors and creative compositions.<\/p>\n\n\n\n<h3 class=\"wp-block-heading\">Internal focusing<\/h3>\n\n\n\n<p class=\"wp-block-paragraph\">The telescope used <strong>WIFD (Internal Focus Design).<\/strong>.That keeps your focus stable, even with heavy cameras.The spiral focus ring works smoothly and precisely.The included <strong>rotator and tilt flange<\/strong> correct tilt and make sure your image stays sharp everywhere.<\/p>\n\n\n\n<figure class=\"wp-block-gallery has-nested-images columns-default is-cropped wp-block-gallery-2 is-layout-flex wp-block-gallery-is-layout-flex\">\n<figure class=\"wp-block-image aligncenter size-large\"><img decoding=\"async\" data-id=\"33722\" src=\"https:\/\/staging.telescoop.nl\/wp-content\/uploads\/2025\/11\/William-Optics-AP-91-448-91-Apochromatische-refractor-BlackCat-WIFD-OTA-7.jpg\" alt=\"William Optics AP 91\/448 91 side view of the full telescope tube.\" class=\"wp-image-33722\" title=\"\"><\/figure>\n<\/figure>\n\n\n\n<h3 class=\"wp-block-heading\">Flexible mounting<\/h3>\n\n\n\n<p class=\"wp-block-paragraph\">The included <strong>dovetail rod<\/strong> works with Arca-Swiss, Vixen standard or via photo wire.This makes it easy to place the telescope on virtually any mount or tripod.<\/p>\n\n\n\n<h3 class=\"wp-block-heading\">Ready to use<\/h3>\n\n\n\n<p class=\"wp-block-paragraph\">Included in delivery is a <strong>protective bag<\/strong> and a <strong>Bahtinov mask<\/strong> included.You can get right into astrophotography or nature photography.The <strong>durable black finish<\/strong> from William Optics looks great and stays beautiful for years.<\/p>\n\n\n\n<h1 class=\"wp-block-heading\"><strong>Specifications<\/strong><\/h1>\n\n\n\n<h3 class=\"wp-block-heading\">Optics<\/h3>\n\n\n\n<figure class=\"wp-block-table\"><table class=\"has-fixed-layout\"><thead><tr><th>Feature<\/th><th>Description<\/th><\/tr><\/thead><tbody><tr><td>Type<\/td><td>Refractor<\/td><\/tr><tr><td>Design<\/td><td>Apochromat<\/td><\/tr><tr><td>Aperture (mm)<\/td><td>91<\/td><\/tr><tr><td>Focal length (mm)<\/td><td>448<\/td><\/tr><tr><td>Focal Ratio (f\/)<\/td><td>4,9<\/td><\/tr><tr><td>Resolution<\/td><td>1,52\u2033<\/td><\/tr><tr><td>Limit value (mag)<\/td><td>12,3<\/td><\/tr><tr><td>Light output<\/td><td>170<\/td><\/tr><tr><td>Max. useful magnification<\/td><td>182\u00d7<\/td><\/tr><tr><td>Tube weight (kg)<\/td><td>6,3<\/td><\/tr><tr><td>Tube length (mm)<\/td><td>556<\/td><\/tr><tr><td>Tube material<\/td><td>Aluminum<\/td><\/tr><tr><td>Coating<\/td><td>Multiple<\/td><\/tr><tr><td>Tube construction<\/td><td>Full tube<\/td><\/tr><tr><td>Lens Design<\/td><td>Quadruplet<\/td><\/tr><tr><td>Free opening (mm)<\/td><td>55<\/td><\/tr><\/tbody><\/table><\/figure>\n\n\n\n<h3 class=\"wp-block-heading\">Focuser<\/h3>\n\n\n\n<figure class=\"wp-block-table\"><table class=\"has-fixed-layout\"><thead><tr><th>Feature<\/th><th>Description<\/th><\/tr><\/thead><tbody><tr><td>Design<\/td><td>Helical (internal)<\/td><\/tr><tr><td>Tilt adapter<\/td><td>Yes<\/td><\/tr><tr><td>Camera connection<\/td><td>M48 \/ M54<\/td><\/tr><tr><td>Rotatable<\/td><td>Yes<\/td><\/tr><\/tbody><\/table><\/figure>\n\n\n\n<h3 class=\"wp-block-heading\">Mount<\/h3>\n\n\n\n<figure class=\"wp-block-table\"><table class=\"has-fixed-layout\"><thead><tr><th>Feature<\/th><th>Description<\/th><\/tr><\/thead><tbody><tr><td>Design<\/td><td>OTA<\/td><\/tr><tr><td>Type of mount<\/td><td>Without<\/td><\/tr><\/tbody><\/table><\/figure>\n\n\n\n<h3 class=\"wp-block-heading\">Included accessories<\/h3>\n\n\n\n<figure class=\"wp-block-table\"><table class=\"has-fixed-layout\"><thead><tr><th>Section<\/th><th>Description<\/th><\/tr><\/thead><tbody><tr><td>Dew cap<\/td><td>Yes<\/td><\/tr><tr><td>Transport bag<\/td><td>Yes<\/td><\/tr><tr><td>Dovetail<\/td><td>Yes<\/td><\/tr><tr><td>Corrector<\/td><td>Integrated<\/td><\/tr><tr><td>Focusing aid<\/td><td>Bahtinov mask<\/td><\/tr><tr><td>Oculai adapter<\/td><td>1,25\u2033 &amp; 2\u2033<\/td><\/tr><\/tbody><\/table><\/figure>\n\n\n\n<h3 class=\"wp-block-heading\">General<\/h3>\n\n\n\n<figure class=\"wp-block-table\"><table class=\"has-fixed-layout\"><thead><tr><th>Feature<\/th><th>Description<\/th><\/tr><\/thead><tbody><tr><td>Series<\/td><td>Cat<\/td><\/tr><tr><td>Color<\/td><td>Black<\/td><\/tr><tr><td>Application<\/td><td>Astrophotography, Moon &amp; Planets, Nature observation, Nebulae &amp; galaxies<\/td><\/tr><tr><td>Sun<\/td><td>No (only with suitable sunscreens)<\/td><\/tr><tr><td>Recommended for<\/td><td>Advanced<\/td><\/tr><tr><td>Observatory use<\/td><td>No<\/td><\/tr><\/tbody><\/table><\/figure>","protected":false},"excerpt":{"rendered":"<p>William Optics AP 91\/448 91 comes with a rotator, tilt lens, M48 and M54 adapters, a versatile dovetail rod, a protective nylon carrying case and a Bahtinov mask integrated into the objective cap for perfect focusing. \u00a0<\/p>","protected":false},"featured_media":97249,"comment_status":"open","ping_status":"closed","template":"","meta":{"_acf_changed":false},"product_brand":[643],"product_cat":[51,567],"product_tag":[],"class_list":["post-33717","product","type-product","status-publish","has-post-thumbnail","product_brand-william-optics","product_cat-telescopen","product_cat-refractors","first","instock","taxable","shipping-taxable","purchasable","product-type-simple"],"bundled_by":[],"bundle_stock_status":"instock","bundle_stock_quantity":null,"bundle_virtual":false,"bundle_layout":"","bundle_add_to_cart_form_location":"","bundle_editable_in_cart":false,"bundle_sold_individually_context":"","bundle_item_grouping":"","bundle_min_size":"","bundle_max_size":"","bundle_price":[],"bundled_items":[],"bundle_sell_ids":[],"acf":[],"jetpack_sharing_enabled":true,"jetpack-related-posts":[{"id":33729,"url":"https:\/\/staging.telescoop.nl\/en\/william-optics-redcat-91-448-apo-wifd-red-ota\/","url_meta":{"origin":33717,"position":0},"title":"William Optics RedCat 91\/448 APO WIFD Red OTA","author":"","date":"14-11-2025","format":false,"excerpt":"William Optics AP 91\/448 91 comes with a protective nylon carrying case, a Bahtinov mask integrated into the objective cap, M48 and M54 camera adapters and a dovetail rod suitable for Arca-Swiss and Losmandy clamps. \u00a0","rel":"","context":"Similar post","block_context":{"text":"Similar post","link":""},"img":{"alt_text":"","src":"https:\/\/i0.wp.com\/staging.telescoop.nl\/wp-content\/uploads\/2025\/11\/William-Optics-AP-91-448-91-Apochromatische-refractor-RedCat-WIFD-OTA-4.jpg?resize=350%2C200&ssl=1","width":350,"height":200,"srcset":"https:\/\/i0.wp.com\/staging.telescoop.nl\/wp-content\/uploads\/2025\/11\/William-Optics-AP-91-448-91-Apochromatische-refractor-RedCat-WIFD-OTA-4.jpg?resize=350%2C200&ssl=1 1x, https:\/\/i0.wp.com\/staging.telescoop.nl\/wp-content\/uploads\/2025\/11\/William-Optics-AP-91-448-91-Apochromatische-refractor-RedCat-WIFD-OTA-4.jpg?resize=525%2C300&ssl=1 1.5x, https:\/\/i0.wp.com\/staging.telescoop.nl\/wp-content\/uploads\/2025\/11\/William-Optics-AP-91-448-91-Apochromatische-refractor-RedCat-WIFD-OTA-4.jpg?resize=700%2C400&ssl=1 2x"},"classes":[]},{"id":33784,"url":"https:\/\/staging.telescoop.nl\/en\/william-optics-91-540-refractor-apo-space-gray-ota\/","url_meta":{"origin":33717,"position":1},"title":"William Optics 91\/540 Refractor APO Space Gray OTA","author":"","date":"14-11-2025","format":false,"excerpt":"William Optics AP 91\/540 comes with retractable dew cap, Bahtinov focus mask, Losmandy swallowtail, sturdy handle, 1:10 rack-and-pinion focuser and deluxe transport bag - ideal for sharp visual observation and astrophotography. \u00a0","rel":"","context":"Similar post","block_context":{"text":"Similar 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Edition","author":"","date":"17-11-2025","format":false,"excerpt":"William Optics FLT91 Flat6A III comes with custom flattener, 2\" telescope connector, camera adapter and fixed flange distance - designed for full field of view adjustment on the FLT 91 refractor.","rel":"","context":"Similar post","block_context":{"text":"Similar post","link":""},"img":{"alt_text":"","src":"https:\/\/i0.wp.com\/staging.telescoop.nl\/wp-content\/uploads\/2025\/11\/William-Optics-FLT91-Flat6A-III-Special-Edition.jpg?resize=350%2C200&ssl=1","width":350,"height":200,"srcset":"https:\/\/i0.wp.com\/staging.telescoop.nl\/wp-content\/uploads\/2025\/11\/William-Optics-FLT91-Flat6A-III-Special-Edition.jpg?resize=350%2C200&ssl=1 1x, https:\/\/i0.wp.com\/staging.telescoop.nl\/wp-content\/uploads\/2025\/11\/William-Optics-FLT91-Flat6A-III-Special-Edition.jpg?resize=525%2C300&ssl=1 1.5x, https:\/\/i0.wp.com\/staging.telescoop.nl\/wp-content\/uploads\/2025\/11\/William-Optics-FLT91-Flat6A-III-Special-Edition.jpg?resize=700%2C400&ssl=1 2x"},"classes":[]},{"id":33699,"url":"https:\/\/staging.telescoop.nl\/en\/william-optics-ap-71-350-71-apochromatische-refractor-redcat-wifd\/","url_meta":{"origin":33717,"position":3},"title":"William Optics AP 71\/350 71 Apochromatic refractor RedCat WIFD","author":"","date":"14-11-2025","format":false,"excerpt":"William Optics AP 71\/350 71 wordt geleverd met een beschermende nylon draagtas, een in de objectiefkap ingebouwd Bahtinov-masker voor perfecte scherpstelling, en een veelzijdige Arca-Swiss & Vixen-Style zwaluwstaart voor eenvoudige montage. \u00a0","rel":"","context":"Similar post","block_context":{"text":"Similar 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refractor MiniCat WIFD OTA","author":"","date":"14-11-2025","format":false,"excerpt":"William Optics AP 51\/178 wordt geleverd met een beschermende nylon draagtas, een ge\u00efntegreerd Bahtinov-masker, dauwkap en een Arca-Swiss & Vixen-Style zwaluwstaart. Deze ultracompacte astrograph is perfect voor op reis en voor astrofotografie met maximale beeldkwaliteit. \u00a0","rel":"","context":"Similar post","block_context":{"text":"Similar post","link":""},"img":{"alt_text":"","src":"https:\/\/i0.wp.com\/staging.telescoop.nl\/wp-content\/uploads\/2025\/11\/William-Optics-AP-51178-Apochromatische-refractor-MiniCat-WIFD-OTA-2.jpg?resize=350%2C200&ssl=1","width":350,"height":200,"srcset":"https:\/\/i0.wp.com\/staging.telescoop.nl\/wp-content\/uploads\/2025\/11\/William-Optics-AP-51178-Apochromatische-refractor-MiniCat-WIFD-OTA-2.jpg?resize=350%2C200&ssl=1 1x, https:\/\/i0.wp.com\/staging.telescoop.nl\/wp-content\/uploads\/2025\/11\/William-Optics-AP-51178-Apochromatische-refractor-MiniCat-WIFD-OTA-2.jpg?resize=525%2C300&ssl=1 1.5x, https:\/\/i0.wp.com\/staging.telescoop.nl\/wp-content\/uploads\/2025\/11\/William-Optics-AP-51178-Apochromatische-refractor-MiniCat-WIFD-OTA-2.jpg?resize=700%2C400&ssl=1 2x"},"classes":[]},{"id":33881,"url":"https:\/\/staging.telescoop.nl\/en\/william-optics-zenithstar-73-430-apo-gold-ota\/","url_meta":{"origin":33717,"position":5},"title":"William Optics ZenithStar 73\/430 APO Gold OTA","author":"","date":"15-11-2025","format":false,"excerpt":"William Optics AP 73\/430 73 comes with tube rings, Vixen-Style dovetail, handle with prism clamp, Bahtinov mask and a soft carrying case, ideal for mobile astrophotography. \u00a0","rel":"","context":"Similar post","block_context":{"text":"Similar post","link":""},"img":{"alt_text":"","src":"https:\/\/i0.wp.com\/staging.telescoop.nl\/wp-content\/uploads\/2025\/11\/William-Optics-AP-73-430-73-Apochromatische-refractor-Super-ZenithStar-Gold-OTA-4.jpg?resize=350%2C200&ssl=1","width":350,"height":200,"srcset":"https:\/\/i0.wp.com\/staging.telescoop.nl\/wp-content\/uploads\/2025\/11\/William-Optics-AP-73-430-73-Apochromatische-refractor-Super-ZenithStar-Gold-OTA-4.jpg?resize=350%2C200&ssl=1 1x, https:\/\/i0.wp.com\/staging.telescoop.nl\/wp-content\/uploads\/2025\/11\/William-Optics-AP-73-430-73-Apochromatische-refractor-Super-ZenithStar-Gold-OTA-4.jpg?resize=525%2C300&ssl=1 1.5x, https:\/\/i0.wp.com\/staging.telescoop.nl\/wp-content\/uploads\/2025\/11\/William-Optics-AP-73-430-73-Apochromatische-refractor-Super-ZenithStar-Gold-OTA-4.jpg?resize=700%2C400&ssl=1 2x"},"classes":[]}],"_links":{"self":[{"href":"https:\/\/staging.telescoop.nl\/en\/wp-json\/wp\/v2\/product\/33717","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/staging.telescoop.nl\/en\/wp-json\/wp\/v2\/product"}],"about":[{"href":"https:\/\/staging.telescoop.nl\/en\/wp-json\/wp\/v2\/types\/product"}],"replies":[{"embeddable":true,"href":"https:\/\/staging.telescoop.nl\/en\/wp-json\/wp\/v2\/comments?post=33717"}],"wp:featuredmedia":[{"embeddable":true,"href":"https:\/\/staging.telescoop.nl\/en\/wp-json\/wp\/v2\/media\/97249"}],"wp:attachment":[{"href":"https:\/\/staging.telescoop.nl\/en\/wp-json\/wp\/v2\/media?parent=33717"}],"wp:term":[{"taxonomy":"product_brand","embeddable":true,"href":"https:\/\/staging.telescoop.nl\/en\/wp-json\/wp\/v2\/product_brand?post=33717"},{"taxonomy":"product_cat","embeddable":true,"href":"https:\/\/staging.telescoop.nl\/en\/wp-json\/wp\/v2\/product_cat?post=33717"},{"taxonomy":"product_tag","embeddable":true,"href":"https:\/\/staging.telescoop.nl\/en\/wp-json\/wp\/v2\/product_tag?post=33717"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}