{"id":34142,"date":"2025-11-17T13:22:10","date_gmt":"2025-11-17T12:22:10","guid":{"rendered":"https:\/\/www.telescoop.nl\/?post_type=product&#038;p=34142"},"modified":"2026-08-25T15:11:41","modified_gmt":"2026-08-25T13:11:41","slug":"william-optics-90-125-zenith-prism-cat-51-wifd","status":"publish","type":"product","link":"https:\/\/www.telescoop.nl\/en\/william-optics-90-125-zenitprisma-cat-51-wifd\/","title":{"rendered":"William Optics 90\u00b0 1.25\u2033 Zenith prism Cat 51 WIFD"},"content":{"rendered":"<h2 class=\"wp-block-heading has-text-align-center\"><strong>William Optics 90\u00b0 1,25&#8243; Zenitprisma Cat 51 WIFD: comfortabel en rechtop kijken door je Cat 51 WIFD<\/strong><\/h2>\n\n\n\n<p class=\"wp-block-paragraph\">This William Optics zenith prism is the visual complement to the Cat 51 WIFD. It bends the light 90 degrees, allowing you to look comfortably into the eyepiece from above, and it presents the image upright: you'll see birds, landscapes, and the moon exactly as they appear outdoors.<\/p>\n\n\n\n<p class=\"wp-block-paragraph\">The BaK-4 prism has a dielectric coating that keeps light transmission high and reflections low. The included 2 to 1.25 inch adapter and ring clamp firmly and scratch-free mount the prism onto the WIFD focuser.<\/p>\n\n\n\n<figure class=\"wp-block-gallery has-nested-images columns-3 is-cropped wp-block-gallery-1 is-layout-flex wp-block-gallery-is-layout-flex\"><figure class=\"wp-block-image\"><img decoding=\"async\" src=\"https:\/\/www.telescoop.nl\/wp-content\/uploads\/2025\/11\/William-Optics-90\u00b0-125-Zenitprism-Cat-51-WIFD.jpg\" alt=\"William Optics 90 Degree Zenith Prism for Cat 51 WIFD\" title=\"\"><\/figure><figure class=\"wp-block-image\"><img decoding=\"async\" src=\"https:\/\/www.telescoop.nl\/wp-content\/uploads\/2025\/11\/William-Optics-90\u00b0-125-Zenitprisma-Cat-51-WIFD-2.jpg\" alt=\"William Optics 90 Degree Zenith Prism for Cat 51 WIFD\" title=\"\"><\/figure><figure class=\"wp-block-image\"><img decoding=\"async\" src=\"https:\/\/www.telescoop.nl\/wp-content\/uploads\/2025\/11\/William-Optics-90\u00b0-125-Zenitprisma-Cat-51-WIFD-1.jpg\" alt=\"William Optics 90 Degree Zenith Prism for Cat 51 WIFD\" title=\"\"><\/figure><\/figure>\n\n\n\n<h4 class=\"wp-block-heading\">Why an erecting prism on an astrograph<\/h4>\n\n\n\n<p class=\"wp-block-paragraph\">The Cat 51 was built as an astrograph, but with this prism and an eyepiece, you have a compact spotting scope and travel binoculars. Two instruments in one case.<\/p>\n\n\n\n<h3 class=\"wp-block-heading\">Featured accessories<\/h3>\n\n\n\n<p class=\"wp-block-paragraph\">Combine with a 1.25-inch low-power eyepiece for the maximum field of view.<\/p>\n\n\n\n<h3 class=\"wp-block-heading\">For whom yes and for whom no<\/h3>\n\n\n\n<ul class=\"wp-block-list\"><li>\u2713 Cat 51 WIFD owners who also want to view visually and during the day<\/li><li>\u2717 RedCat 51 owners: choose the version with an M56 adapter<\/li><\/ul>\n\n\n\n<h3 class=\"wp-block-heading\">Specifications<\/h3>\n\n\n\n<figure class=\"wp-block-table\"><table class=\"has-fixed-layout\"><tbody><tr><td><strong>Type<\/strong><\/td><td>Zenith prism 90 degrees, inverting<\/td><\/tr><tr><td><strong>Glass<\/strong><\/td><td>BaK-4, dielectric coating<\/td><\/tr><tr><td><strong>Assembly<\/strong><\/td><td>2 to 1.25 inch adapter with ring clamp (Cat 51 WIFD)<\/td><\/tr><tr><td><strong>Image<\/strong><\/td><td>Upright, laterally correct<\/td><\/tr><\/tbody><\/table><\/figure>\n\n\n\n<p class=\"wp-block-paragraph\">You can find more accessories for this merk at the <a href=\"\/en\/brands\/william-optics\/\">William Optics merk Page<\/a>.<\/p>","protected":false},"excerpt":{"rendered":"<p>William Optics 90 Degree Zenith Prism for Cat 51 WIFD: dielectric coated BaK-4 prism with 2 to 1.25 inch adapter and compression ring. Erect image for nature and moon.<\/p>","protected":false},"featured_media":97578,"comment_status":"open","ping_status":"closed","template":"","meta":{"_acf_changed":false},"product_brand":[643],"product_cat":[56,591,3142],"product_tag":[],"class_list":["post-34142","product","type-product","status-publish","has-post-thumbnail","product_brand-william-optics","product_cat-telescoop-accessoires","product_cat-diagonalen","product_cat-zenitspiegels-en-zenitprisma-diagonals","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":34141,"url":"https:\/\/www.telescoop.nl\/en\/william-optics-90-125-zenitprisma-redcat\/","url_meta":{"origin":34142,"position":0},"title":"William Optics 90\u00b0 1.25\u2033 Zenith prism RedCat","author":"","date":"17-11-2025","format":false,"excerpt":"William Optics 90-degree zenith prism for the RedCat 51: BAK-4 prism with anti-reflection coating, M56 mount with ring clamp and 1.25-inch eyepiece side. Erect, laterally correct image.","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-RedCat-2.jpg?resize=350%2C200&ssl=1","width":350,"height":200},"classes":[]},{"id":33664,"url":"https:\/\/www.telescoop.nl\/en\/william-optics-ap-51-250-apochromatische-refractor-spacecat-wifd-ota\/","url_meta":{"origin":34142,"position":1},"title":"William Optics AP 51\/250 Apochromatic Refractor SpaceCat WIFD OTA","author":"","date":"14-11-2025","format":false,"excerpt":"William Optics SpaceCat 51 WIFD: the same f\/4.9 Petzval optics as the RedCat 51 in the SpaceCat version, featuring an internal focuser. Supplied with a Bahtinov mask, dovetail bar, and carrying case.","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-SpaceCat-WIFD-OTA-1.jpg?resize=350%2C200&ssl=1","width":350,"height":200},"classes":[]},{"id":33659,"url":"https:\/\/www.telescoop.nl\/en\/william-optics-ap-51-250-apochromatische-refractor-redcat-wifd\/","url_meta":{"origin":34142,"position":2},"title":"William Optics AP 51\/250 Apochromatic Refractor RedCat WIFD OTA","author":"","date":"14-11-2025","format":false,"excerpt":"William Optics RedCat 51 WIFD: the most famous compact astrograph with a four-element Petzval optical design (FPL53\/FPL51) and internal focuser. Flat, color-corrected image up to full-frame. 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":33652,"url":"https:\/\/www.telescoop.nl\/en\/william-optics-ap-51-178-apochromatische-refractor-minicat-wifd-ota\/","url_meta":{"origin":34142,"position":3},"title":"William Optics AP 51\/178 Apochromatic refractor MiniCat WIFD OTA","author":"","date":"14-11-2025","format":false,"excerpt":"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.","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-51178-Apochromatische-refractor-MiniCat-WIFD-OTA-1.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":34142,"position":4},"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 flagship 108\/518 f\/4.8 with integrated Petzval corrector, rotator, tilt adapter, and internal focuser. Supplied with Bahtinov mask and Vixen dovetail.","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":34218,"url":"https:\/\/www.telescoop.nl\/en\/william-optics-45-125-op-125-amici-prisma\/","url_meta":{"origin":34142,"position":5},"title":"William Optics 45\u00b0, 1.25\u2033 on 1.25\u2033 Amici prism","author":"","date":"17-11-2025","format":false,"excerpt":"William Optics 45-degree erecting Amici prism 1.25 inch: BaK-4 glass with fully multi-coated optics and brass ring clamp. Erect, true-to-life image for nature and astronomy.","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-45%C2%B0-125-op-125-Amici-prisma.jpg?resize=350%2C200&ssl=1","width":350,"height":200},"classes":[]}],"_links":{"self":[{"href":"https:\/\/www.telescoop.nl\/en\/wp-json\/wp\/v2\/product\/34142","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=34142"}],"wp:featuredmedia":[{"embeddable":true,"href":"https:\/\/www.telescoop.nl\/en\/wp-json\/wp\/v2\/media\/97578"}],"wp:attachment":[{"href":"https:\/\/www.telescoop.nl\/en\/wp-json\/wp\/v2\/media?parent=34142"}],"wp:term":[{"taxonomy":"product_brand","embeddable":true,"href":"https:\/\/www.telescoop.nl\/en\/wp-json\/wp\/v2\/product_brand?post=34142"},{"taxonomy":"product_cat","embeddable":true,"href":"https:\/\/www.telescoop.nl\/en\/wp-json\/wp\/v2\/product_cat?post=34142"},{"taxonomy":"product_tag","embeddable":true,"href":"https:\/\/www.telescoop.nl\/en\/wp-json\/wp\/v2\/product_tag?post=34142"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}