{"product_id":"william-optics-gt81-grand-turismo-refractor-with-wifd-focuser-gold-t-gt-81gd-wifd","title":"William Optics GT81 Grand Turismo Refractor with WIFD Focuser - Gold - T-GT-81GD-WIFD","description":"\u003ccenter\u003e\u003ciframe width=\"560\" height=\"315\" src=\"https:\/\/www.youtube.com\/embed\/fSj8gG_PK1g\" title=\"YouTube video player\" frameborder=\"0\" allow=\"accelerometer; autoplay; clipboard-write; encrypted-media; gyroscope; picture-in-picture; web-share\" allowfullscreen=\"\"\u003e\u003c\/iframe\u003e\u003c\/center\u003e\n\u003cp\u003eThe William Optics GT81 Triplet Refractor has a focal length of 478 mm and an f\/ratio of f\/5.9.  FPL-53 glass is used in the optical system to reduce chromatic aberration and produce sharp, high contrast images, whether using the GT81 for observing or astrophotography.\u003c\/p\u003e\n\u003cp\u003e\u003cem\u003eThis GT71 WIFD model is white with gold trim; it is also available in red or space gray at the same price.  We may show other colors if the image itself is helpful.  Just remember that you will get a white\/gold telescope, regardless of the colors you see on this page.  Thanks.\u003c\/em\u003e\u003cbr\u003e\u003c\/p\u003e\n\u003ch3\u003e\u003cem\u003e\u003c\/em\u003e\u003c\/h3\u003e\n\u003ch3\u003e\u003cspan\u003eWIFD Technology\u003c\/span\u003e\u003c\/h3\u003e\n\u003cp\u003e\u003cspan\u003eThe William Optics Internal Focus Design, or WIFD, is an innovative and revolutionary design that combines a precision internal focusing mechanism with high quality optics, providing the ultimate apochromatic refractor for astrophotography. \u003c\/span\u003e\u003c\/p\u003e\n\u003cp\u003e\u003cspan\u003eDesigned from the ground up with the ability to handle the newest generation of large, heavy, high-resolution cooled cameras, the rock-solid optical tube assembly is uncompromised in quality. The movement of the focuser is integrated inside the main tube assembly, so there are no movements of a focuser drawtube visible from the outside.  The user can enjoy the benefits of a traditional two speed fine focuser, while not worrying about limitations typically found in traditional rear mounted focusers. \u003c\/span\u003e\u003c\/p\u003e\n\u003ch3\u003e\u003cspan\u003eIncluded Accessories\u003c\/span\u003e\u003c\/h3\u003e\n\u003cul\u003e\n\u003cli\u003e\n\u003cspan style=\"font-size: 0.875rem;\"\u003eGT81 f\/5.9 Tube Assembly - White with Gold Trim\u003c\/span\u003e\u003cbr\u003e\n\u003c\/li\u003e\n\u003cli\u003e\n\u003cspan style=\"font-size: 0.875rem;\"\u003eDust Cover with Bahtinov Mask\u003c\/span\u003e\u003cbr\u003e\n\u003c\/li\u003e\n\u003cli\u003e\n\u003cspan style=\"font-size: 0.875rem;\"\u003e120 mm Saddle Handle Bar\u003c\/span\u003e\u003cbr\u003e\n\u003c\/li\u003e\n\u003cli\u003e\n\u003cspan style=\"font-size: 0.875rem;\"\u003eCamera Angle Rotator\u003c\/span\u003e\u003cbr\u003e\n\u003c\/li\u003e\n\u003cli\u003e\n\u003cspan style=\"font-size: 0.875rem;\"\u003eM92 to M63 Adapter\u003c\/span\u003e\u003cbr\u003e\n\u003c\/li\u003e\n\u003cli\u003e\n\u003cspan style=\"font-size: 0.875rem;\"\u003e210 Vixen-Style Dovetail Plate\u003c\/span\u003e\u003cbr\u003e\n\u003c\/li\u003e\n\u003cli\u003e\n\u003cspan style=\"font-size: 0.875rem;\"\u003eSoft Carry Case\u003c\/span\u003e\u003cbr\u003e\n\u003c\/li\u003e\n\u003cli\u003e\n\u003cspan style=\"font-size: 0.875rem;\"\u003eZYGO Test Report\u003c\/span\u003e\u003cbr\u003e\n\u003c\/li\u003e\n\u003c\/ul\u003e\n\u003cp\u003e\u003cspan\u003e\u003cimg style=\"display: block; margin-left: auto; margin-right: auto;\" height=\"677\" width=\"525\" src=\"https:\/\/cdn.shopify.com\/s\/files\/1\/0851\/2766\/files\/GT81_Highlights_480x480.png?v=1686265273\" alt=\"Highlights of the William Optics GT81 WIFD Refractor\"\u003e\u003c\/span\u003e\u003c\/p\u003e\n\u003ch3 style=\"text-align: center;\"\u003e\u003cspan\u003eSpecifications\u003c\/span\u003e\u003c\/h3\u003e\n\u003cul\u003e\n\u003cli\u003e\n\u003cspan style=\"font-size: 0.875rem;\"\u003eLens Design:  APO Triplet with 1 FPL-53 Element\u003c\/span\u003e\u003cbr\u003e\n\u003c\/li\u003e\n\u003cli\u003e\n\u003cspan style=\"font-size: 0.875rem;\"\u003eAperture:  81 mm\u003c\/span\u003e\u003cbr\u003e\n\u003c\/li\u003e\n\u003cli\u003e\n\u003cspan style=\"font-size: 0.875rem;\"\u003eFocal Length:  478 mm\u003c\/span\u003e\u003cbr\u003e\n\u003c\/li\u003e\n\u003cli\u003e\n\u003cspan style=\"font-size: 0.875rem;\"\u003eFocal Ratio:  f.5.9\u003c\/span\u003e\u003cbr\u003e\n\u003c\/li\u003e\n\u003cli\u003e\n\u003cspan style=\"font-size: 0.875rem;\"\u003eFocuser:  WIFD\u003c\/span\u003e\u003cbr\u003e\n\u003c\/li\u003e\n\u003cli\u003e\n\u003cspan style=\"font-size: 0.875rem;\"\u003eImage Circle:  45 mm (Full Frame)\u003c\/span\u003e\u003cbr\u003e\n\u003c\/li\u003e\n\u003cli\u003e\n\u003cspan style=\"font-size: 0.875rem;\"\u003eRetracted Length:  421 mm\u003c\/span\u003e\u003cbr\u003e\n\u003c\/li\u003e\n\u003cli\u003e\n\u003cspan style=\"font-size: 0.875rem;\"\u003eExtended Length:  502 mm\u003c\/span\u003e\u003cbr\u003e\n\u003c\/li\u003e\n\u003cli\u003e\n\u003cspan style=\"font-size: 0.875rem;\"\u003eDew Shield Circumference:  382 mm\u003c\/span\u003e\u003cbr\u003e\n\u003c\/li\u003e\n\u003cli\u003e\n\u003cspan style=\"font-size: 0.875rem;\"\u003eDew Shield Diameter:  121 mm\u003c\/span\u003e\u003cbr\u003e\n\u003c\/li\u003e\n\u003cli\u003e\n\u003cspan style=\"font-size: 0.875rem;\"\u003eWeight of OTA Only:  3.58kg\u003c\/span\u003e\u003cbr\u003e\n\u003c\/li\u003e\n\u003cli\u003e\n\u003cspan style=\"font-size: 0.875rem;\"\u003eWeight of OTA with Ring, Dovetail \u0026amp; Saddle:  4.565kg\u003c\/span\u003e\u003cbr\u003e\n\u003c\/li\u003e\n\u003cli\u003e\n\u003cspan style=\"font-size: 0.875rem;\"\u003eColor:  White with Gold Trim\u003c\/span\u003e\u003cbr\u003e\n\u003c\/li\u003e\n\u003cli\u003e\n\u003cspan style=\"font-size: 0.875rem;\"\u003eStrehl Ratio:  0.95+\u003c\/span\u003e\u003cbr\u003e\n\u003c\/li\u003e\n\u003cli\u003e\n\u003cspan style=\"font-size: 0.875rem;\"\u003eTest Report:  Included\u003c\/span\u003e\u003cbr\u003e\n\u003c\/li\u003e\n\u003cli\u003e\n\u003cspan style=\"font-size: 0.875rem;\"\u003eOptional Flattener:  FLAT6AIII 0.8X or FLAT68III 1X, which requires an WIFD Extension Adapter\u003c\/span\u003e\u003cbr\u003e\n\u003c\/li\u003e\n\u003c\/ul\u003e","brand":"William Optics","offers":[{"title":"Default Title","offer_id":40203997970545,"sku":"WIL-T-GT-81GD-WIFD","price":1957.95,"currency_code":"EUR","in_stock":true}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0851\/2766\/files\/GT81_WIFD_Gold_Side.jpg?v=1776459043","url":"https:\/\/khanscope.com\/en-fr\/products\/william-optics-gt81-grand-turismo-refractor-with-wifd-focuser-gold-t-gt-81gd-wifd","provider":"Khan Scope Centre","version":"1.0","type":"link"}