{"id":33676,"date":"2025-11-14T13:08:34","date_gmt":"2025-11-14T12:08:34","guid":{"rendered":"https:\/\/www.telescoop.nl\/?post_type=product&#038;p=33676"},"modified":"2026-10-13T11:15:24","modified_gmt":"2026-10-13T09:15:24","slug":"william-optics-ap-61-300-61-apochromatic-refractor-redcat-ota","status":"publish","type":"product","link":"https:\/\/www.telescoop.nl\/en\/william-optics-ap-61-300-61-apochromatische-refractor-redcat-ota\/","title":{"rendered":"William Optics AP 61\/300 61 Apochromatic Refractor RedCat OTA"},"content":{"rendered":"<h2 class=\"wp-block-heading has-text-align-center\"><strong>Quadruplet with field rotator: more openness, more detail<\/strong><\/h2>\n\n\n\n<p class=\"wp-block-paragraph\">The <strong>William Optics RedCat 61<\/strong> The Cat-concept moves to a 61 mm aperture and 300 mm focal length. The quadruplet optics provide a bright, sharp, and flat image across the entire frame, and the built-in field rotator precisely positions your composition without disturbing the focus.<\/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=\"33677\" src=\"https:\/\/www.telescoop.nl\/wp-content\/uploads\/2025\/11\/William-Optics-AP-61-300-61-Apochromatische-refractor-RedCat-OTA-1.jpg\" alt=\"William Optics RedCat 61 Apochromatic Astrograph, Full Frame\" class=\"wp-image-33677\" 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-61-300-61-Apochromatische-refractor-RedCat-OTA-2.jpg\" alt=\"The RedCat 61 with field rotator and tube rings\" class=\"wp-image-33678\" 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\">Made for serious deep-sky compositions<\/h4>\n\n\n\n<p class=\"wp-block-paragraph\">The Petzval design with integrated corrector keeps stars round all the way to the corners of a full-frame sensor. At f\/4.9, exposures remain short and noise low. The included tube rings and Arca\/Vixen dovetail provide a stable, flex-free mount for camera and guidescope.<\/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>RedCat 61\/300 Optical Tube with Integrated Corrector<\/li>\n\n\n\n<li>Field rotator<\/li>\n\n\n\n<li>Tube Rings<\/li>\n\n\n\n<li>Arca-Swiss &amp; Vixen-Style Prism Rail<\/li>\n\n\n\n<li>Bahtinov mask<\/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 deep-sky photographers making the leap from a 51mm refractor to more aperture and scale, while maintaining portability. Not for those primarily seeking maximum sky fields; the MiniCat or RedCat 51 remains the specialist for that.<\/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, quadruplet Petzval with corrector<\/td><\/tr><tr><td>Opening<\/td><td>61 mm<\/td><\/tr><tr><td>Focal length<\/td><td>300 mm<\/td><\/tr><tr><td>Opening ratio<\/td><td>f\/4,9<\/td><\/tr><tr><td>Field rotator<\/td><td>Built-in<\/td><\/tr><tr><td>Field of view<\/td><td>Flat to full-frame<\/td><\/tr><tr><td>Attachment<\/td><td>Mounting rings with Arca\/Vixen prism rail<\/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><strong>This is just the tube (OTA), without mounting and tripod.<\/strong> You can choose the appropriate mounting and the accessories that come with it below.<\/p>\n<p>William Optics RedCat 61: f\/4.9 61\/300 quadruplet apochromat with built-in field rotator and corrector. Includes tube rings, Arca\/Vixen dovetail, Bahtinov mask, and carrying case.<\/p>","protected":false},"featured_media":97213,"comment_status":"open","ping_status":"closed","template":"","meta":{"_acf_changed":false},"product_brand":[643],"product_cat":[51,428,3175,567],"product_tag":[3352,3353],"class_list":["post-33676","product","type-product","status-publish","has-post-thumbnail","product_brand-william-optics","product_cat-telescopen","product_cat-telescopen-voor-astrofotografie","product_cat-refractor-ota","product_cat-refractor-telescopen","product_tag-sterrenkijker","product_tag-sterrenkijkers","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":[27281,90626,32949,31090,34220,15860,34141,33941,33946],"acf":[],"jetpack_sharing_enabled":true,"jetpack-related-posts":[{"id":111636,"url":"https:\/\/www.telescoop.nl\/en\/zwo-seestar-s50-pro\/","url_meta":{"origin":33676,"position":0},"title":"ZWO Seestar S50 Pro","author":"Info telescoop","date":"25-08-2026","format":false,"excerpt":"The ZWO Seestar S50 Pro is the successor to the Seestar S50: 50 mm quadruplet APO (260 mm, f\/5.2), two 8.3 MP 4K sensors, a 63-degree wide-angle camera for the Milky Way up to 8K, three built-in filters, a 10,000 mAh battery (up to 9 hours), and 128 GB of storage. Four capture modes for...","rel":"","context":"With 5 comments","block_context":{"text":"With 5 comments","link":"https:\/\/www.telescoop.nl\/en\/zwo-seestar-s50-pro\/#comments"},"img":{"alt_text":"ZWO Seestar S50 Pro hero","src":"https:\/\/i0.wp.com\/www.telescoop.nl\/wp-content\/uploads\/2026\/08\/zwo-seestar-s50-pro.jpg?resize=350%2C200&ssl=1","width":350,"height":200,"srcset":"https:\/\/i0.wp.com\/www.telescoop.nl\/wp-content\/uploads\/2026\/08\/zwo-seestar-s50-pro.jpg?resize=350%2C200&ssl=1 1x, https:\/\/i0.wp.com\/www.telescoop.nl\/wp-content\/uploads\/2026\/08\/zwo-seestar-s50-pro.jpg?resize=525%2C300&ssl=1 1.5x, https:\/\/i0.wp.com\/www.telescoop.nl\/wp-content\/uploads\/2026\/08\/zwo-seestar-s50-pro.jpg?resize=700%2C400&ssl=1 2x"},"classes":[]}],"_links":{"self":[{"href":"https:\/\/www.telescoop.nl\/en\/wp-json\/wp\/v2\/product\/33676","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=33676"}],"wp:featuredmedia":[{"embeddable":true,"href":"https:\/\/www.telescoop.nl\/en\/wp-json\/wp\/v2\/media\/97213"}],"wp:attachment":[{"href":"https:\/\/www.telescoop.nl\/en\/wp-json\/wp\/v2\/media?parent=33676"}],"wp:term":[{"taxonomy":"product_brand","embeddable":true,"href":"https:\/\/www.telescoop.nl\/en\/wp-json\/wp\/v2\/product_brand?post=33676"},{"taxonomy":"product_cat","embeddable":true,"href":"https:\/\/www.telescoop.nl\/en\/wp-json\/wp\/v2\/product_cat?post=33676"},{"taxonomy":"product_tag","embeddable":true,"href":"https:\/\/www.telescoop.nl\/en\/wp-json\/wp\/v2\/product_tag?post=33676"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}