{"id":33911,"date":"2025-11-15T14:24:36","date_gmt":"2025-11-15T13:24:36","guid":{"rendered":"https:\/\/www.telescoop.nl\/?post_type=product&#038;p=33911"},"modified":"2026-07-18T13:43:19","modified_gmt":"2026-07-18T11:43:19","slug":"william-optics-pleiades-181-998-apo-septuplet-astrograph-ota","status":"publish","type":"product","link":"https:\/\/www.telescoop.nl\/en\/william-optics-pleiades-181-998-apo-septuplet-astrograph-ota\/","title":{"rendered":"William Optics Pleiades 181\/998 APO Septuplet Astrograph OTA"},"content":{"rendered":"<h2 class=\"wp-block-heading has-text-align-center\"><strong>Pleiades 181: Seven-element astrophotograph for full frame<\/strong><\/h2>\n\n\n\n<p class=\"wp-block-paragraph\">The <strong>William Optics Pleiades 181<\/strong> is a pure astrograph, built around a seven-element optical design with FPL-53 glass and integrated corrector. Stars remain sharp points even in the corners of a full-frame sensor, without a separate flattener. The absolute top model: 181 mm aperture in a corrected seven-element system, for observatory-class results.<\/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=\"33912\" src=\"https:\/\/www.telescoop.nl\/wp-content\/uploads\/2025\/11\/William-Optics-181-AP-181-998-Apochromatische-refractor-Pleiades-Astrograph-OTA-1.jpg\" alt=\"William Optics Pleiades 181 apochromatic astrograph, full field\" class=\"wp-image-33912\" 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-181-AP-181-998-Apochromatische-refractor-Pleiades-Astrograph-OTA-4.jpg\" alt=\"The Pleiades 181 with camera adapters\" class=\"wp-image-33915\" 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\">Fast system, short exposures<\/h4>\n\n\n\n<p class=\"wp-block-paragraph\">With a 181 mm aperture and a 998 mm focal length (f\/5.5), this is a fast photographic system: lots of signal in a short time, allowing for deeper exposures per night. The included camera adapters directly connect common phototrains, and the Bahtinov mask allows for precise focusing. This is a camera instrument: visual use with eyepieces is not what this tube is designed for.<\/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>Optical tube Pleiades 181\/998 with seven-element optics<\/li>\n\n\n\n<li>3.7 inch rack-and-pinion focuser<\/li>\n\n\n\n<li>Integrated corrector<\/li>\n\n\n\n<li>M48-, M54-, and M68-camera adapters<\/li>\n\n\n\n<li>Losmandy dovetail<\/li>\n\n\n\n<li>Handle<\/li>\n\n\n\n<li>Bahtinov mask<\/li>\n\n\n\n<li>Transport 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 Guiding Scope<\/a> completes the setup for long exposures; choose the size that fits your mount and 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 the demanding astrophotographer with an observatory or heavy-duty permanent setup seeking refractor-class perfection. Not for almost anyone else; this is a small observatory-class instrument with corresponding mount requirements.<\/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>Apochromatic astrograph, 7 elements with FPL-53<\/td><\/tr><tr><td>Opening<\/td><td>181 mm<\/td><\/tr><tr><td>Focal length<\/td><td>998 mm<\/td><\/tr><tr><td>Opening ratio<\/td><td>f\/5,5<\/td><\/tr><tr><td>Field of view<\/td><td>Flat and corrected to full-frame<\/td><\/tr><tr><td>Use<\/td><td>Astrophotography (camera-instrument)<\/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 Pleiades 181: seven-element FPL-53 astrograph 181\/998 f\/5.5 with integrated corrector and flat full-frame image. Pure photography tube with camera adapters and Bahtinov mask.<\/p>","protected":false},"featured_media":97397,"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-33911","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":33917,"url":"https:\/\/www.telescoop.nl\/en\/william-optics-pleiades-68-260-apo-astrograph-ota\/","url_meta":{"origin":33911,"position":0},"title":"William Optics Pleiades 68\/260 APO Astrograph OTA","author":"","date":"15-11-2025","format":false,"excerpt":"William Optics Pleiades 68: zevenelements FPL-53 astrograaf 68\/260 f\/3,8 met ge\u00efntegreerde corrector en vlak full-frame beeld. Pure fotografiebuis met camera-adapters en Bahtinov-masker.","rel":"","context":"Similar post","block_context":{"text":"Similar post","link":""},"img":{"alt_text":"","src":"","width":0,"height":0},"classes":[]},{"id":33903,"url":"https:\/\/www.telescoop.nl\/en\/william-optics-pleiades-111-528-apo-septuplet-astrograph-ota\/","url_meta":{"origin":33911,"position":1},"title":"William Optics Pleiades 111\/528 APO Septuplet Astrograph OTA","author":"","date":"15-11-2025","format":false,"excerpt":"William Optics Pleiades 111: zevenelements FPL-53 astrograaf 111\/528 f\/4,8 met ge\u00efntegreerde corrector en vlak full-frame beeld. Pure fotografiebuis met camera-adapters en Bahtinov-masker.","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-111-AP-111-528-Apochromatische-refractor-Pleiades-Astrograph-OTA-3.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":33911,"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":33676,"url":"https:\/\/www.telescoop.nl\/en\/william-optics-ap-61-300-61-apochromatische-refractor-redcat-ota\/","url_meta":{"origin":33911,"position":3},"title":"William Optics AP 61\/300 61 Apochromatic Refractor RedCat OTA","author":"","date":"14-11-2025","format":false,"excerpt":"William Optics RedCat 61: quadruplet apochromaat 61\/300 f\/4,9 met ingebouwde veldrotator en corrector. Geleverd met buisringen, Arca\/Vixen-prismabalk, Bahtinov-masker 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-61-300-61-Apochromatische-refractor-RedCat-OTA-2.jpg?resize=350%2C200&ssl=1","width":350,"height":200},"classes":[]},{"id":34051,"url":"https:\/\/www.telescoop.nl\/en\/william-optics-61-guidescope-guide-star-apo-goud\/","url_meta":{"origin":33911,"position":4},"title":"William Optics 61 Guidescope Guide Star Apo Gold","author":"","date":"16-11-2025","format":false,"excerpt":"William Optics GuideStar 61 apo guidescope (gold) with FPL-53 lens: accurate guiding for refractors from 700 to 1200 mm. Includes Vixen rail 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-Guidescope-Guide-Star-Apo-61-4.jpg?resize=350%2C200&ssl=1","width":350,"height":200},"classes":[]},{"id":34058,"url":"https:\/\/www.telescoop.nl\/en\/william-optics-61-guidescope-guide-star-apo-blue\/","url_meta":{"origin":33911,"position":5},"title":"William Optics 61 Guidescope Guide Star Apo Blue","author":"","date":"16-11-2025","format":false,"excerpt":"William Optics GuideStar 61 apo guidescope (blauw) met FPL-53-objectief: nauwkeurige guiding voor refractors van 700 tot 1200 mm. Inclusief Vixen-rail 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-Guidescope-Guide-Star-Apo-61-10.jpg?resize=350%2C200&ssl=1","width":350,"height":200},"classes":[]}],"_links":{"self":[{"href":"https:\/\/www.telescoop.nl\/en\/wp-json\/wp\/v2\/product\/33911","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=33911"}],"wp:featuredmedia":[{"embeddable":true,"href":"https:\/\/www.telescoop.nl\/en\/wp-json\/wp\/v2\/media\/97397"}],"wp:attachment":[{"href":"https:\/\/www.telescoop.nl\/en\/wp-json\/wp\/v2\/media?parent=33911"}],"wp:term":[{"taxonomy":"product_brand","embeddable":true,"href":"https:\/\/www.telescoop.nl\/en\/wp-json\/wp\/v2\/product_brand?post=33911"},{"taxonomy":"product_cat","embeddable":true,"href":"https:\/\/www.telescoop.nl\/en\/wp-json\/wp\/v2\/product_cat?post=33911"},{"taxonomy":"product_tag","embeddable":true,"href":"https:\/\/www.telescoop.nl\/en\/wp-json\/wp\/v2\/product_tag?post=33911"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}