{"id":33729,"date":"2025-11-14T14:36:19","date_gmt":"2025-11-14T13:36:19","guid":{"rendered":"https:\/\/www.telescoop.nl\/?post_type=product&#038;p=33729"},"modified":"2026-05-18T16:10:49","modified_gmt":"2026-05-18T14:10:49","slug":"william-optics-redcat-91-448-apo-wifd-red-ota","status":"publish","type":"product","link":"https:\/\/www.telescoop.nl\/en\/william-optics-redcat-91-448-apo-wifd-red-ota\/","title":{"rendered":"William Optics RedCat 91\/448 APO WIFD Red OTA"},"content":{"rendered":"<h3 class=\"wp-block-heading\">Compact and powerful RedCat for photography<\/h3>\n\n\n\n<p class=\"wp-block-paragraph\">The <strong>William Optics AP 91\/448 91 RedCat<\/strong> is perfect for astrophotography and nature photography.It combines compact size with high optical quality.It <strong>Petzval design with FPL53 and FPL51 glass<\/strong> gives a color-clean, sharp image across the entire field.Your sensor sees everything, even up to full-frame size.<\/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=\"33730\" src=\"https:\/\/www.telescoop.nl\/wp-content\/uploads\/2025\/11\/William-Optics-AP-91-448-91-Apochromatische-refractor-RedCat-WIFD-OTA-4.jpg\" alt=\"William Optics AP 91\/448 91 RedCat WIFD OTA red apochromatic refractor telescope.\" class=\"wp-image-33730\" title=\"\"><\/figure>\n<\/figure>\n\n\n\n<h3 class=\"wp-block-heading\">Fast and clear<\/h3>\n\n\n\n<p class=\"wp-block-paragraph\">With a <strong>91 mm lens and f\/4.9<\/strong> capture a lot of light.That means short exposures and sharp details, even for faint stars.The <strong>field of view of more than 55 mm<\/strong> lets you create creative compositions without distortion.<\/p>\n\n\n\n<h3 class=\"wp-block-heading\">Internal focusing<\/h3>\n\n\n\n<p class=\"wp-block-paragraph\">The <strong>WIFD focus<\/strong> works internally, so heavy cameras don't disturb anything.Turn the spiral ring and focus precisely.The included <strong>rotator and tilt flange<\/strong> Keep your image sharp everywhere.<\/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=\"33733\" src=\"https:\/\/www.telescoop.nl\/wp-content\/uploads\/2025\/11\/William-Optics-AP-91-448-91-Apochromatische-refractor-RedCat-WIFD-OTA-1.jpg\" alt=\"William Optics AP 91\/448 91 with the included black nylon carrying case with the Cat logo.\" class=\"wp-image-33733\" title=\"\"><\/figure>\n<\/figure>\n\n\n\n<h3 class=\"wp-block-heading\">Flexible mounting<\/h3>\n\n\n\n<p class=\"wp-block-paragraph\">The included <strong>dovetail rod<\/strong> works with Arca-Swiss, Vixen stand or photo wire.So you easily attach the telescope to any tripod or astronomical mount.<\/p>\n\n\n\n<h3 class=\"wp-block-heading\">Ready to use<\/h3>\n\n\n\n<p class=\"wp-block-paragraph\">Included in delivery is a <strong>tote bag<\/strong> and a <strong>Bahtinov mask<\/strong> included.You can start night or nature photography right away.The durable <strong>red finish<\/strong> From William Optics stays beautiful for years<\/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>91<\/td><\/tr><tr><td>Focal length (mm)<\/td><td>448<\/td><\/tr><tr><td>Focal Ratio (f\/)<\/td><td>4,9<\/td><\/tr><tr><td>Resolution<\/td><td>1,52\u2033<\/td><\/tr><tr><td>Limit value (mag)<\/td><td>12,3<\/td><\/tr><tr><td>Light output<\/td><td>170<\/td><\/tr><tr><td>Max. useful magnification<\/td><td>182\u00d7<\/td><\/tr><tr><td>Tube weight (kg)<\/td><td>6,3<\/td><\/tr><tr><td>Tube length (mm)<\/td><td>556<\/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>Lens Design<\/td><td>Quadruplet<\/td><\/tr><tr><td>Free opening (mm)<\/td><td>55<\/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>Design<\/td><td>Helical (internal)<\/td><\/tr><tr><td>Tilt adapter<\/td><td>Yes<\/td><\/tr><tr><td>Camera connection<\/td><td>M48 \/ M54<\/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>Dovetail<\/td><td>Yes<\/td><\/tr><tr><td>Corrector<\/td><td>Integrated<\/td><\/tr><tr><td>Focusing aid<\/td><td>Bahtinov mask<\/td><\/tr><tr><td>Oculai adapter<\/td><td>1,25\u2033 &amp; 2\u2033<\/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>Red<\/td><\/tr><tr><td>Observation goals<\/td><td>Astrophotography, Moon &amp; Planets, Nature observation, Nebulae &amp; galaxies<\/td><\/tr><tr><td>Sun<\/td><td>No (only with suitable sunscreens)<\/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 91\/448 91 comes with a protective nylon carrying case, a Bahtinov mask integrated into the objective cap, M48 and M54 camera adapters and a dovetail rod suitable for Arca-Swiss and Losmandy clamps. \u00a0<\/p>","protected":false},"featured_media":97260,"comment_status":"open","ping_status":"closed","template":"","meta":{"_acf_changed":false},"product_brand":[643],"product_cat":[51,3175,567],"product_tag":[],"class_list":["post-33729","product","type-product","status-publish","has-post-thumbnail","product_brand-william-optics","product_cat-telescopen","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":105495,"url":"https:\/\/www.telescoop.nl\/en\/levenhuk-new-skyline-pro-16\/","url_meta":{"origin":33729,"position":0},"title":"Levenhuk 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