{"id":34141,"date":"2025-11-17T13:22:06","date_gmt":"2025-11-17T12:22:06","guid":{"rendered":"https:\/\/www.telescoop.nl\/?post_type=product&#038;p=34141"},"modified":"2026-08-23T15:09:38","modified_gmt":"2026-08-23T13:09:38","slug":"william-optics-90-125-zenith-prism-redcat","status":"publish","type":"product","link":"https:\/\/www.telescoop.nl\/en\/william-optics-90-125-zenitprisma-redcat\/","title":{"rendered":"William Optics 90\u00b0 1.25\u2033 Zenith prism RedCat"},"content":{"rendered":"<h2 class=\"wp-block-heading has-text-align-center\"><strong>William Optics 90\u00b0 1,25&#8243; Zenitprisma RedCat: van je RedCat een spotting scope maken<\/strong><\/h2>\n\n\n\n<p class=\"wp-block-paragraph\">This William Optics diagonal prism is made for the RedCat 51 (51\/250 apo) and turns that astrograph into a visual instrument in a jiffy. The prism deflects the light 90 degrees and renders the image upright and laterally correct: exactly as you see it with the naked eye.<\/p>\n\n\n\n<p class=\"wp-block-paragraph\">The BAK-4 precision glass with anti-reflection coating keeps light transmission high and contrast sharp; the matte black interior suppresses stray light. Via the M56 connection with a clamping ring, the prism sits securely and scratch-free on the RedCat, and the 1.25-inch side accepts any standard eyepiece.<\/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-RedCat-1.jpg\" alt=\"William Optics 90 Degree Zenith Prism for RedCat 51\" 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-RedCat-2.jpg\" alt=\"William Optics 90 Degree Zenith Prism for RedCat 51\" 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-RedCat-3.jpg\" alt=\"William Optics 90 Degree Zenith Prism for RedCat 51\" 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-RedCat-4.jpg\" alt=\"William Optics 90 Degree Zenith Prism for RedCat 51\" 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-RedCat-5.jpg\" alt=\"William Optics 90 Degree Zenith Prism for RedCat 51\" 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-RedCat-6.jpg\" alt=\"William Optics 90 Degree Zenith Prism for RedCat 51\" title=\"\"><\/figure><\/figure>\n\n\n\n<h4 class=\"wp-block-heading\">Nature by day, moon by night<\/h4>\n\n\n\n<p class=\"wp-block-paragraph\">With upright imaging, the RedCat suddenly becomes an excellent spotting scope for birds and landscapes. And at night, you can recognize moon craters directly, without mental mirroring.<\/p>\n\n\n\n<h3 class=\"wp-block-heading\">Featured accessories<\/h3>\n\n\n\n<p class=\"wp-block-paragraph\">Combine the prism with a 1.25-inch eyepiece of your choice; with a low magnification, you'll get the most out of the RedCat's wide field.<\/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 RedCat 51 owners who also want to use their astrograph visually<\/li><li>\u2713 Nature observers who go out with the RedCat during the day<\/li><li>\u2717 Owners of the Cat 51 WIFD: there is a dedicated prism version for that.<\/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, anti-reflective coating<\/td><\/tr><tr><td><strong>Telescope silk<\/strong><\/td><td>M56 with ring clamp (RedCat 51)<\/td><\/tr><tr><td><strong>Ocular view<\/strong><\/td><td>1.25 inches<\/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 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.<\/p>","protected":false},"featured_media":97580,"comment_status":"open","ping_status":"closed","template":"","meta":{"_acf_changed":false},"product_brand":[643],"product_cat":[56,591,3142],"product_tag":[],"class_list":["post-34141","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":34142,"url":"https:\/\/www.telescoop.nl\/en\/william-optics-90-125-zenitprisma-cat-51-wifd\/","url_meta":{"origin":34141,"position":0},"title":"William Optics 90\u00b0 1.25\u2033 Zenith prism Cat 51 WIFD","author":"","date":"17-11-2025","format":false,"excerpt":"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.","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":33659,"url":"https:\/\/www.telescoop.nl\/en\/william-optics-ap-51-250-apochromatische-refractor-redcat-wifd\/","url_meta":{"origin":34141,"position":1},"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":34218,"url":"https:\/\/www.telescoop.nl\/en\/william-optics-45-125-op-125-amici-prisma\/","url_meta":{"origin":34141,"position":2},"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":[]},{"id":33664,"url":"https:\/\/www.telescoop.nl\/en\/william-optics-ap-51-250-apochromatische-refractor-spacecat-wifd-ota\/","url_meta":{"origin":34141,"position":3},"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":33676,"url":"https:\/\/www.telescoop.nl\/en\/william-optics-ap-61-300-61-apochromatische-refractor-redcat-ota\/","url_meta":{"origin":34141,"position":4},"title":"William Optics AP 61\/300 61 Apochromatic Refractor RedCat OTA","author":"","date":"14-11-2025","format":false,"excerpt":"William Optics RedCat 61: f\/4.9 61\/300 quadruplet apochromat with built-in field rotator and corrector. 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