{"id":33664,"date":"2025-11-14T12:34:15","date_gmt":"2025-11-14T11:34:15","guid":{"rendered":"https:\/\/www.telescoop.nl\/?post_type=product&#038;p=33664"},"modified":"2026-03-03T20:24:24","modified_gmt":"2026-03-03T19:24:24","slug":"william-optics-ap-51-250-apochromatic-refractor-spacecat-wifd-ota","status":"publish","type":"product","link":"https:\/\/staging.telescoop.nl\/en\/william-optics-ap-51-250-apochromatische-refractor-spacecat-wifd-ota\/","title":{"rendered":"William Optics AP 51\/250 Apochromatic refractor SpaceCat WIFD OTA"},"content":{"rendered":"<h3 class=\"wp-block-heading\">Compact, light and instantly ready for strong photos<\/h3>\n\n\n\n<p class=\"wp-block-paragraph\">The <strong>William Optics AP 51\/250<\/strong> is made for photographers who want a clear, sharp image quickly.You get a bright tube that weighs little, is easy to carry and gives instant results.The wide image stays tight to the corners, so you spend less time post-processing and more time shooting.<\/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=\"33667\" src=\"https:\/\/staging.telescoop.nl\/wp-content\/uploads\/2025\/11\/William-Optics-AP-51250-Apochromatische-refractor-SpaceCat-WIFD-OTA-2.jpg\" alt=\"William Optics AP 51\/250 side view mounted on the dovetail rod.\" class=\"wp-image-33667\" title=\"\"><\/figure>\n<\/figure>\n\n\n\n<h3 class=\"wp-block-heading\">Clear image without fuss<\/h3>\n\n\n\n<p class=\"wp-block-paragraph\">The Petzval design works like a built-in corrector.So you don't have to use a separate flattener.Your image remains flat, color-clean and clear-even with a full-frame camera.So you can just point, focus and start shooting.<\/p>\n\n\n\n<h3 class=\"wp-block-heading\">Focus quickly and remain stable<\/h3>\n\n\n\n<p class=\"wp-block-paragraph\">The focuser works by rotating around the tube.You turn the ring and the image slides smoothly into focus.Even with a heavy camera, everything remains stable.This prevents shifting or tilt and keeps your shot sharp.<\/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=\"33675\" src=\"https:\/\/staging.telescoop.nl\/wp-content\/uploads\/2025\/11\/William-Optics-AP-51250-Apochromatische-refractor-SpaceCat-WIFD-OTA-10.jpg\" alt=\"William Optics AP 51\/250 complete side view of the SpaceCat OTA.\" class=\"wp-image-33675\" title=\"\"><\/figure>\n<\/figure>\n\n\n\n<h3 class=\"wp-block-heading\">Fits almost any mount<\/h3>\n\n\n\n<p class=\"wp-block-paragraph\">The 110 mm dovetail gives you three mounting options:Arca-Swiss, Vixen or regular tripod screw.This makes it easy to put the telescope on a photo tripod, a star tracker or an astronomical mount.Useful if you often photograph outdoors or travel a lot.<\/p>\n\n\n\n<h3 class=\"wp-block-heading\">Cleverly designed for convenient operation<\/h3>\n\n\n\n<p class=\"wp-block-paragraph\">The dew hood hides a Bahtinov mask.You take it out, focus precisely, and snap it back.The included bag protects your telescope and makes transportation easy.Everything feels compact, sturdy and well thought out.<\/p>\n\n\n\n<h3 class=\"wp-block-heading\">For night and detail work<\/h3>\n\n\n\n<p class=\"wp-block-paragraph\">You'll capture large nebulae, star fields and bright deep-sky objects with nice contrast.The fast f\/4.9 aperture allows for short exposures, so your photos get clear quickly with less noise.Perfect for those who want to capture a lot in one night.<\/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>51<\/td><\/tr><tr><td>Focal length (mm)<\/td><td>250<\/td><\/tr><tr><td>Focal Ratio (f\/)<\/td><td>4,9<\/td><\/tr><tr><td>Resolution<\/td><td>2,71\u2033<\/td><\/tr><tr><td>Limit value (mag)<\/td><td>10,3<\/td><\/tr><tr><td>Light output<\/td><td>50<\/td><\/tr><tr><td>Max. useful magnification<\/td><td>102\u00d7<\/td><\/tr><tr><td>Tube weight (kg)<\/td><td>2,4<\/td><\/tr><tr><td>Tube length (mm)<\/td><td>346<\/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>Dew cap diameter (mm)<\/td><td>80<\/td><\/tr><tr><td>Lens Design<\/td><td>Quadruplet<\/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>Tilt adapter<\/td><td>Yes<\/td><\/tr><tr><td>Design<\/td><td>Helical<\/td><\/tr><tr><td>Camera connection<\/td><td>M48<\/td><\/tr><tr><td>Backfocus (mm)<\/td><td>59,7<\/td><\/tr><tr><td>Free opening (mm)<\/td><td>48<\/td><\/tr><tr><td>Adjustment range (mm)<\/td><td>0-23<\/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>Focus Mask<\/td><td>Yes<\/td><\/tr><tr><td>Dovetail<\/td><td>Arca-Swiss &amp; Vixen-Style<\/td><\/tr><tr><td>Tripod screw<\/td><td>1\/4\u2033<\/td><\/tr><tr><td>Corrector<\/td><td>Integrated<\/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>Silver<\/td><\/tr><tr><td>Application<\/td><td>Astrophotography, Moon &amp; Planets, Deep-sky<\/td><\/tr><tr><td>Sun<\/td><td>Yes (with appropriate filters)<\/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 51\/250 comes with a protective nylon carrying case, an integrated Bahtinov mask for perfect focusing and a versatile Arca-Swiss\/Vixen-style dovetail rod, ideal for astrophotographers looking for a compact, high-quality telescope. \u00a0<\/p>","protected":false},"featured_media":97204,"comment_status":"open","ping_status":"closed","template":"","meta":{"_acf_changed":false},"product_brand":[643],"product_cat":[51,567],"product_tag":[],"class_list":["post-33664","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":33659,"url":"https:\/\/staging.telescoop.nl\/en\/william-optics-ap-51-250-apochromatische-refractor-redcat-wifd\/","url_meta":{"origin":33664,"position":0},"title":"William Optics AP 51\/250 Apochromatic refractor RedCat WIFD","author":"","date":"14-11-2025","format":false,"excerpt":"William Optics AP 51\/250 wordt geleverd met een beschermende nylon draagtas, ge\u00efntegreerd Bahtinov-masker en een veelzijdige Arca-Swiss & Vixen-stijl prismabalk \u2013 perfect voor astrofotografen die een compacte, kleurzuivere en hoogwaardige apochromatische refractor zoeken. \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-51250-Apochromatische-refractor-RedCat-WIFD-1.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-51250-Apochromatische-refractor-RedCat-WIFD-1.jpg?resize=350%2C200&ssl=1 1x, https:\/\/i0.wp.com\/staging.telescoop.nl\/wp-content\/uploads\/2025\/11\/William-Optics-AP-51250-Apochromatische-refractor-RedCat-WIFD-1.jpg?resize=525%2C300&ssl=1 1.5x, https:\/\/i0.wp.com\/staging.telescoop.nl\/wp-content\/uploads\/2025\/11\/William-Optics-AP-51250-Apochromatische-refractor-RedCat-WIFD-1.jpg?resize=700%2C400&ssl=1 2x"},"classes":[]},{"id":33652,"url":"https:\/\/staging.telescoop.nl\/en\/william-optics-ap-51-178-apochromatische-refractor-minicat-wifd-ota\/","url_meta":{"origin":33664,"position":1},"title":"William Optics AP 51\/178 Apochromatic 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":34141,"url":"https:\/\/staging.telescoop.nl\/en\/william-optics-90-125-zenitprisma-redcat\/","url_meta":{"origin":33664,"position":2},"title":"William Optics 90\u00b0 1.25\u2033 Zenith prism RedCat","author":"","date":"17-11-2025","format":false,"excerpt":"William Optics 90\u00b0 comes with silver zenith prism, 1.25\" eyepiece connector, M56 telescope connector and ring clamp - perfect for RedCat 51 nature observation with upright viewing.","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-90%C2%B0-125-Zenitprisma-RedCat-1.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-90%C2%B0-125-Zenitprisma-RedCat-1.jpg?resize=350%2C200&ssl=1 1x, https:\/\/i0.wp.com\/staging.telescoop.nl\/wp-content\/uploads\/2025\/11\/William-Optics-90%C2%B0-125-Zenitprisma-RedCat-1.jpg?resize=525%2C300&ssl=1 1.5x, https:\/\/i0.wp.com\/staging.telescoop.nl\/wp-content\/uploads\/2025\/11\/William-Optics-90%C2%B0-125-Zenitprisma-RedCat-1.jpg?resize=700%2C400&ssl=1 2x"},"classes":[]},{"id":33869,"url":"https:\/\/staging.telescoop.nl\/en\/william-optics-zenithstar-61-360-apo-ii-ota\/","url_meta":{"origin":33664,"position":3},"title":"William Optics ZenithStar 61\/360 APO II OTA","author":"","date":"15-11-2025","format":false,"excerpt":"William Optics AP 61\/360 ZS61 II wordt geleverd met een UniGuide 32mm guidescope, een flattener, buisringen, Arca-Swiss & Vixen-style zwaluwstaart, 2\" naar 1,25\" adapter en een zachte draagtas. \u00a0","rel":"","context":"Similar post","block_context":{"text":"Similar 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2x"},"classes":[]},{"id":33903,"url":"https:\/\/staging.telescoop.nl\/en\/william-optics-pleiades-111-528-apo-septuplet-astrograph-ota\/","url_meta":{"origin":33664,"position":4},"title":"William Optics Pleiades 111\/528 APO Septuplet Astrograph OTA","author":"","date":"15-11-2025","format":false,"excerpt":"William Optics 111 AP 111\/528 wordt geleverd met een ge\u00efntegreerde 7-lens corrector, WIDF interne focuser, Vixen-Style zwaluwstaart, handvat, Bahtinov-masker, M54 & M48 camera adapters en een zachte draagtas. \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-111-AP-111-528-Apochromatische-refractor-Pleiades-Astrograph-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-111-AP-111-528-Apochromatische-refractor-Pleiades-Astrograph-OTA-2.jpg?resize=350%2C200&ssl=1 1x, https:\/\/i0.wp.com\/staging.telescoop.nl\/wp-content\/uploads\/2025\/11\/William-Optics-111-AP-111-528-Apochromatische-refractor-Pleiades-Astrograph-OTA-2.jpg?resize=525%2C300&ssl=1 1.5x, https:\/\/i0.wp.com\/staging.telescoop.nl\/wp-content\/uploads\/2025\/11\/William-Optics-111-AP-111-528-Apochromatische-refractor-Pleiades-Astrograph-OTA-2.jpg?resize=700%2C400&ssl=1 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