{"id":33652,"date":"2025-11-14T11:44:09","date_gmt":"2025-11-14T10:44:09","guid":{"rendered":"https:\/\/www.telescoop.nl\/?post_type=product&#038;p=33652"},"modified":"2026-07-18T13:21:02","modified_gmt":"2026-07-18T11:21:02","slug":"william-optics-ap-51-178-apochromatic-refractor-minicat-wifd-ota","status":"publish","type":"product","link":"https:\/\/www.telescoop.nl\/en\/william-optics-ap-51-178-apochromatische-refractor-minicat-wifd-ota\/","title":{"rendered":"William Optics AP 51\/178 Apochromatic refractor MiniCat WIFD OTA"},"content":{"rendered":"<h2 class=\"wp-block-heading has-text-align-center\"><strong>The smallest cat: 178 mm focal length at f\/3.5<\/strong><\/h2>\n\n\n\n<p class=\"wp-block-paragraph\">The <strong>William Optics MiniCat 51\/178 WIFD<\/strong> is made for photographers who want to think big in a small format. With a focal length of 178 mm and an aperture of f\/3.5, you can capture large sky fields: complete constellations, the Milky Way, and vast nebulae, with short exposures and low noise.<\/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 size-large\"><img decoding=\"async\" data-id=\"33654\" src=\"https:\/\/www.telescoop.nl\/wp-content\/uploads\/2025\/11\/William-Optics-AP-51178-Apochromatische-refractor-MiniCat-WIFD-OTA-2.jpg\" alt=\"William Optics MiniCat 51\/178 apochromatic astrograph, field flattener\" class=\"wp-image-33654\" title=\"\"><\/figure>\n<\/figure>\n\n\n\n<div class=\"wp-block-columns is-layout-flex wp-container-core-columns-is-layout-8d39b2df wp-block-columns-is-layout-flex\">\n<div class=\"wp-block-column is-layout-flow wp-block-column-is-layout-flow\">\n<figure class=\"wp-block-image size-full\"><img decoding=\"async\" src=\"https:\/\/www.telescoop.nl\/wp-content\/uploads\/2025\/11\/William-Optics-AP-51178-Apochromatische-refractor-MiniCat-WIFD-OTA-3.jpg\" alt=\"De MiniCat 51\/178 with internal WIFD focuser\" class=\"wp-image-33655\" title=\"\"><\/figure>\n<\/div>\n\n\n\n<div class=\"wp-block-column is-layout-flow wp-block-column-is-layout-flow\">\n<h4 class=\"wp-block-heading\">Six-element optical system with internal focusing<\/h4>\n\n\n\n<p class=\"wp-block-paragraph\">The six-element lens design keeps stars round and tight even into the corners, without a separate flattener. The internal WIFD focuser does not move weight externally, so your balance remains stable and your camera rotates without sagging. The Bahtinov mask is integrated into the dew shield for quick and precise focusing.<\/p>\n<\/div>\n<\/div>\n\n\n\n<h3 class=\"wp-block-heading\"><strong>In the box<\/strong><\/h3>\n\n\n\n<ul class=\"wp-block-list\">\n<li>MiniCat 51\/178 Optical Tube with WIFD Focuser<\/li>\n\n\n\n<li>Integrated Bahtinov mask<\/li>\n\n\n\n<li>Dew cap<\/li>\n\n\n\n<li>Arca-Swiss and Vixen-Style dovetail<\/li>\n\n\n\n<li>Nylon tote bag<\/li>\n<\/ul>\n\n\n\n<h3 class=\"wp-block-heading\"><strong>Featured accessories<\/strong><\/h3>\n\n\n\n<p class=\"wp-block-paragraph\">A <a href=\"https:\/\/www.telescoop.nl\/en\/telescope-accessories\/astro-photography\/other-astrophotography-accessories\/\">William Optics UniGuide 32mm Guidescope<\/a> (159 euros) completes the setup for long exposures. William Optics' M48 camera adapters are available for common mounts; choose the variant for your camera.<\/p>\n\n\n\n<h4 class=\"wp-block-heading\">For whom yes, for whom no<\/h4>\n\n\n\n<p class=\"wp-block-paragraph\">For: Astrophotographers who want to capture wide sky fields with a lightweight travel setup or star tracker. Not for: those seeking image scale for smaller nebulae or galaxies; look to the RedCat 71 or Cat 91 class.<\/p>\n\n\n\n<h3 class=\"wp-block-heading\"><strong>Specifications<\/strong><\/h3>\n\n\n\n<figure class=\"wp-block-table\"><table><tbody><tr><td>Optical design<\/td><td>Apochromat, six-element Petzval design<\/td><\/tr><tr><td>Opening<\/td><td>51 mm<\/td><\/tr><tr><td>Focal length<\/td><td>178 mm<\/td><\/tr><tr><td>Opening ratio<\/td><td>f\/3,5<\/td><\/tr><tr><td>Focuser<\/td><td>WIFD (intern)<\/td><\/tr><tr><td>Focus assist<\/td><td>Integrated Bahtinov mask<\/td><\/tr><tr><td>Attachment<\/td><td>Arca-Swiss and Vixen-Style<\/td><\/tr><tr><td>Execution<\/td><td>OTA (loose tube)<\/td><\/tr><\/tbody><\/table><\/figure>\n\n\n\n<p class=\"wp-block-paragraph\">Unsure about the right tube for your camera and mount? The <a href=\"https:\/\/www.telescoop.nl\/en\/telescope-selection-aid\/\">telescope selection aid<\/a> helps you choose. Also view all <a href=\"https:\/\/www.telescoop.nl\/en\/telescopes\/refracting-telescopes\/\">Refracting telescopes<\/a> and the full range of <a href=\"https:\/\/www.telescoop.nl\/en\/brands\/william-optics\/\">William Optics<\/a>.<\/p>","protected":false},"excerpt":{"rendered":"<p>William Optics MiniCat 51\/178 WIFD: ultra-compact f\/3.5 apochromat with internal focuser for wide-field astrophotography. Supplied with Bahtinov mask, dew shield, Arca\/Vixen dovetail, and carrying case.<\/p>","protected":false},"featured_media":97194,"comment_status":"open","ping_status":"closed","template":"","meta":{"_acf_changed":false},"product_brand":[643],"product_cat":[51,428,531,3175,567],"product_tag":[],"class_list":["post-33652","product","type-product","status-publish","has-post-thumbnail","product_brand-william-optics","product_cat-telescopen","product_cat-telescopen-voor-astrofotografie","product_cat-gevorderd","product_cat-refractor-ota","product_cat-refractor-telescopen","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":33664,"url":"https:\/\/www.telescoop.nl\/en\/william-optics-ap-51-250-apochromatische-refractor-spacecat-wifd-ota\/","url_meta":{"origin":33652,"position":0},"title":"William Optics AP 51\/250 Apochromatic Refractor SpaceCat WIFD OTA","author":"","date":"14-11-2025","format":false,"excerpt":"William Optics SpaceCat 51 WIFD: dezelfde f\/4,9 Petzval-optiek als de RedCat 51 in de SpaceCat-uitvoering, met interne focuser. 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Delivered with Bahtinov mask, prism rail, and carrying bag.","rel":"","context":"Similar post","block_context":{"text":"Similar post","link":""},"img":{"alt_text":"","src":"https:\/\/i0.wp.com\/www.telescoop.nl\/wp-content\/uploads\/2025\/11\/William-Optics-AP-51250-Apochromatische-refractor-RedCat-WIFD-4.jpg?resize=350%2C200&ssl=1","width":350,"height":200},"classes":[]},{"id":33639,"url":"https:\/\/www.telescoop.nl\/en\/william-optics-ap-108-518-apochromatische-refractor-ultracat-wifd\/","url_meta":{"origin":33652,"position":2},"title":"William Optics AP 108\/518 Apochromatic Refractor UltraCat WIFD OTA","author":"","date":"14-11-2025","format":false,"excerpt":"William Optics UltraCat 108 WIFD: full-frame vlaggenschip 108\/518 f\/4,8 met ge\u00efntegreerde Petzval-corrector, rotator, kantelflens en interne focuser. Geleverd met Bahtinov-masker en Vixen-zwaluwstaart.","rel":"","context":"Similar post","block_context":{"text":"Similar post","link":""},"img":{"alt_text":"","src":"https:\/\/i0.wp.com\/www.telescoop.nl\/wp-content\/uploads\/2025\/11\/William-Optics-Apochromatische-refractor-AP-108-518-UltraCat-WIFD.jpg?resize=350%2C200&ssl=1","width":350,"height":200},"classes":[]},{"id":34142,"url":"https:\/\/www.telescoop.nl\/en\/william-optics-90-125-zenitprisma-cat-51-wifd\/","url_meta":{"origin":33652,"position":3},"title":"William Optics 90\u00b0 1.25\" Zenith prism Cat 51 WIFD","author":"","date":"17-11-2025","format":false,"excerpt":"William Optics 90 graden zenitprisma voor de Cat 51 WIFD: dielektrisch gecoat BaK-4 prisma met 2 naar 1,25 inch adapter en ringklem. Rechtopstaand beeld voor natuur en maan.","rel":"","context":"Similar post","block_context":{"text":"Similar post","link":""},"img":{"alt_text":"","src":"https:\/\/i0.wp.com\/www.telescoop.nl\/wp-content\/uploads\/2025\/11\/William-Optics-90%C2%B0-125-Zenitprisma-Cat-51-WIFD-2.jpg?resize=350%2C200&ssl=1","width":350,"height":200},"classes":[]},{"id":33709,"url":"https:\/\/www.telescoop.nl\/en\/william-optics-ultracat-76-365-apo-wifd-30th-anniversary-edition-ota\/","url_meta":{"origin":33652,"position":4},"title":"William Optics UltraCat 76\/365 APO WIFD 30th Anniversary Edition OTA","author":"","date":"14-11-2025","format":false,"excerpt":"William Optics UltraCat 76 WIFD 30th Anniversary: genummerde jubileum-apochromaat 76\/365 f\/4,8 met interne focuser, geleverd met UniGuide 32 mm richtkijker, Bahtinov-masker, certificaat en transporttas.","rel":"","context":"Similar post","block_context":{"text":"Similar post","link":""},"img":{"alt_text":"","src":"https:\/\/i0.wp.com\/www.telescoop.nl\/wp-content\/uploads\/2025\/11\/William-Optics-AP-76-365-76-30th-Apochromatische-refractor-UltraCat-WIFD-Anniversary-Edition-6.jpg?resize=350%2C200&ssl=1","width":350,"height":200},"classes":[]},{"id":33894,"url":"https:\/\/www.telescoop.nl\/en\/william-optics-zenithstar-81-559-apo-wifd-red-ota\/","url_meta":{"origin":33652,"position":5},"title":"William Optics ZenithStar 81\/559 APO WIFD Red OTA","author":"","date":"15-11-2025","format":false,"excerpt":"William Optics ZenithStar 81 WIFD Red: FPL-53 apochromaat 81\/559 f\/6,9 met interne focuser, rode uitvoering. Geleverd met buisringen, Arca\/Vixen-zwaluwstaart, handvat, Bahtinov-masker, adapters en draagtas.","rel":"","context":"Similar post","block_context":{"text":"Similar post","link":""},"img":{"alt_text":"","src":"https:\/\/i0.wp.com\/www.telescoop.nl\/wp-content\/uploads\/2025\/11\/William-Optics-AP-81-559-81-Apochromatische-refractor-ZenithStar-WIFD-Red-OTA-3.jpg?resize=350%2C200&ssl=1","width":350,"height":200},"classes":[]}],"_links":{"self":[{"href":"https:\/\/www.telescoop.nl\/en\/wp-json\/wp\/v2\/product\/33652","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/www.telescoop.nl\/en\/wp-json\/wp\/v2\/product"}],"about":[{"href":"https:\/\/www.telescoop.nl\/en\/wp-json\/wp\/v2\/types\/product"}],"replies":[{"embeddable":true,"href":"https:\/\/www.telescoop.nl\/en\/wp-json\/wp\/v2\/comments?post=33652"}],"wp:featuredmedia":[{"embeddable":true,"href":"https:\/\/www.telescoop.nl\/en\/wp-json\/wp\/v2\/media\/97194"}],"wp:attachment":[{"href":"https:\/\/www.telescoop.nl\/en\/wp-json\/wp\/v2\/media?parent=33652"}],"wp:term":[{"taxonomy":"product_brand","embeddable":true,"href":"https:\/\/www.telescoop.nl\/en\/wp-json\/wp\/v2\/product_brand?post=33652"},{"taxonomy":"product_cat","embeddable":true,"href":"https:\/\/www.telescoop.nl\/en\/wp-json\/wp\/v2\/product_cat?post=33652"},{"taxonomy":"product_tag","embeddable":true,"href":"https:\/\/www.telescoop.nl\/en\/wp-json\/wp\/v2\/product_tag?post=33652"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}