{"id":9505,"date":"2021-03-12T08:01:37","date_gmt":"2021-03-12T08:01:37","guid":{"rendered":"https:\/\/amt.ee\/?post_type=product&#038;p=9505"},"modified":"2025-05-30T06:20:35","modified_gmt":"2025-05-30T06:20:35","slug":"william-optics-apochromatic-refractor-ap-51-250-redcat-51-ota","status":"publish","type":"product","link":"https:\/\/amt.ee\/en\/product\/william-optics-apochromatic-refractor-ap-51-250-redcat-51-ota\/","title":{"rendered":"William Optics Apochromatic refractor 51\/250 RedCat 51 OTA"},"content":{"rendered":"<p><a href=\"https:\/\/amt.ee\/wp-content\/uploads\/2021\/03\/sttr_mar2021_williamoptics-redcat51_reprint.pdf\">STTR_Mar2021_WilliamOptics-Redcat51_Reprint<\/a> &#8211; review<\/p>\n<p><iframe loading=\"lazy\" title=\"Ultra Versatile Telephoto Lens, Redcat 250mm f\/4.9 by William Optics\" width=\"640\" height=\"360\" src=\"https:\/\/www.youtube.com\/embed\/Ii16qtlTW2I?feature=oembed\" frameborder=\"0\" allow=\"accelerometer; autoplay; clipboard-write; encrypted-media; gyroscope; picture-in-picture\" allowfullscreen><\/iframe><\/p>\n<p>The\u00a0<b>AP 51\/250 refractor<\/b>\u00a0is an impressive combination of compact size, attractive price and outstanding optical quality which is suitable for all\u00a0<b>astro- and nature photography<\/b>. At the heart of the optical set-up is the\u00a0<b>Petzval design<\/b>\u00a0comprising four elements in three groups in which FPL53 and FPL51 glass has been utilised. The result is a colour-rich corrected image field with a diameter of more than 44 mm &#8211; perfect for\u00a0<b>full-frame cameras<\/b>. The fast focal ratio of f\/4.9 allows short exposure times.<\/p>\n<p>For camera connection there is a\u00a0<b>M48 thread<\/b>. Appropriate T2 adapters. Focusing is <b>helical<\/b>\u00a0&#8211; so by twisting the textured ring on the telescope body even heavy cameras are no problem.<\/p>\n<p>The 110mm long dovetail bar offers three connection alternatives; screw connection with a photo thread, Arca Swiss or Vixen standard fittings. With these three options it should be no problem to connect this telescope to all the usual photo tripods, photo mounts or astronomical mounts.<\/p>\n<p>Not only is a protective\u00a0<b>nylon carrying case<\/b>\u00a0included, but also a specially devised\u00a0<b>Bahtinov mask<\/b>. This mask helps with focusing and is built into the lens cap.<\/p>\n<p>A telescope such as the RedCat 51 is ideal for photographers who are interested in the night sky and also animal photography.<\/p>\n<p>With the RedCat 51 you are not only investing in impressive optical performance, but you will also be thrilled by the durable and beautiful finish\u00a0<i>William Optics<\/i>\u00a0has achieved.<\/p>\n<p><iframe loading=\"lazy\" title=\"William Optics RedCat 51 (Unboxing)\" width=\"640\" height=\"360\" src=\"https:\/\/www.youtube.com\/embed\/XEqjSouILKg?feature=oembed\" frameborder=\"0\" allow=\"accelerometer; autoplay; clipboard-write; encrypted-media; gyroscope; picture-in-picture\" allowfullscreen><\/iframe><\/p>\n","protected":false},"excerpt":{"rendered":"<ul>\n<li>refracting telescope,\u00a0<strong>Very Good for Astrophotography<\/strong>\u00a0and nature observation<\/li>\n<li>a soft carrying case for transportation is included<\/li>\n<li>telescope aperture: 51mm \/ focal length: 250mm<\/li>\n<li>Max. useful magnification: 102x<\/li>\n<li>total weight: 1,5 kg<\/li>\n<li>scope of supply: telescope, soft case, No other accessories incl.<\/li>\n<\/ul>\n","protected":false},"featured_media":9509,"comment_status":"open","ping_status":"closed","template":"","meta":[],"product_brand":[],"product_cat":[45],"product_tag":[],"class_list":{"0":"post-9505","1":"product","2":"type-product","3":"status-publish","4":"has-post-thumbnail","6":"product_cat-astrophotography","8":"first","9":"instock","10":"taxable","11":"shipping-taxable","12":"purchasable","13":"product-type-simple"},"yoast_head":"<!-- This site is optimized with the Yoast SEO plugin v25.2 - https:\/\/yoast.com\/wordpress\/plugins\/seo\/ -->\n<title>William Optics Apochromatic refractor 51\/250 RedCat 51 OTA<\/title>\n<meta name=\"description\" content=\"refracting telescope,\u00a0Very Good for Astrophotography\u00a0and nature observation  a soft carrying case for transportation is included  telescope aperture: 51mm \/ focal length: 250mm  Max. useful magnification: 102x  total weight: 1,5 kg  scope of supply: telescope, soft case, No other accessories incl.\" \/>\n<meta name=\"robots\" content=\"index, follow, max-snippet:-1, max-image-preview:large, max-video-preview:-1\" \/>\n<link rel=\"canonical\" href=\"https:\/\/amt.ee\/en\/product\/william-optics-apochromatic-refractor-ap-51-250-redcat-51-ota\/\" \/>\n<meta property=\"og:locale\" content=\"en_US\" \/>\n<meta property=\"og:type\" content=\"article\" \/>\n<meta property=\"og:title\" content=\"William Optics Apochromatic refractor 51\/250 RedCat 51 OTA\" \/>\n<meta property=\"og:description\" content=\"refracting telescope,\u00a0Very Good for Astrophotography\u00a0and nature observation  a soft carrying case for transportation is included  telescope aperture: 51mm \/ focal length: 250mm  Max. useful magnification: 102x  total weight: 1,5 kg  scope of supply: telescope, soft case, No other accessories incl.\" \/>\n<meta property=\"og:url\" content=\"https:\/\/amt.ee\/en\/product\/william-optics-apochromatic-refractor-ap-51-250-redcat-51-ota\/\" \/>\n<meta property=\"og:site_name\" content=\"Astro &amp; 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