{"product_id":"william-optics-cat71-redcat-71-mm-f-4-9-petzval-apo-refractor-t-c-71rd","title":"William Optics Red Cat71 - RedCat 71 mm f\/4.9 Refractor - T-C-71RD","description":"\u003cp\u003e\u003cspan style=\"color: rgb(255, 42, 0);\"\u003e\u003cem\u003e\u003cstrong\u003eHurry, just one left at an amazing price!\u003c\/strong\u003e\u003c\/em\u003e\u003c\/span\u003e\u003c\/p\u003e\n\u003cp\u003eThe William Optics RedCat refractor continues to be immensely popular, but if you'd like more aperture, check out the 71 mm f\/4.9 RedCat!  This beautifully designed Petzval astrograph sports four optical elements in a three group configuration (2-1-1).  The doublet front group is made of FPL-53 glass, followed by one central element and a rear lens.  This optical design produces a flat image plane on its own, with an image circle of over 45 mm, without the need for a flattener.  With an image circle this big, the RedCat 71 is compatible with full frame or APS-C sensors.\u003c\/p\u003e\n\u003cp\u003eThe William Optics Cat71 comes with a built-in Bahtinov mask to assist in focusing, and a calibrated helical focuser.  The lockable helical focuser has a large surface area that makes it easy to focus, even with gloves.  It's gear ring has 153 teeth, which is more precise than most camera lenses.  Behind the focuser is a camera angle rotator with tension knob and a tilt adapter, which ends in M48 threads.\u003c\/p\u003e\n\u003cp\u003eThe RedCat 71 comes complete with a saddle handlebar on top.  This handle accepts accessories such as a finder or guide scope but is raised above the focuser enough to serve as a carry handle. A pair of super sturdy mounting rings are also included and attach to an Arca Swiss\/Vixen style plate, making it easy to connect the Cat71 to a telescope mount or heavy-duty camera tripod.\u003c\/p\u003e\n\u003cp\u003eWhen you're not using your telescope, you can store it in the included soft carry bag!\u003c\/p\u003e\n\u003ch3\u003eSpecifications:\u003c\/h3\u003e\n\u003cp\u003eFocal Length:  348 mm\u003c\/p\u003e\n\u003cp\u003eDiameter:  71 mm\u003c\/p\u003e\n\u003cp\u003eFocal Ratio:  f\/4.9\u003c\/p\u003e\n\u003cp\u003eImage Circle:  \u0026gt;44 mm\u003c\/p\u003e\n\u003cp\u003eFocuser:  Helical with 2GT Gear Ring\u003c\/p\u003e\n\u003cp\u003eTube Length with Dew Shield:  435 mm\u003c\/p\u003e\n\u003cp\u003eWeight of OTA:  2.8kg \/ 6.2 lb.\u003c\/p\u003e\n\u003cp\u003eWeight of OTA with Hardware:  3.7kg \/ 8.2 lb.\u003c\/p\u003e","brand":"William Optics","offers":[{"title":"Default Title","offer_id":39583084052593,"sku":"WIL-T-C-71RD","price":1186.95,"currency_code":"EUR","in_stock":true}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0851\/2766\/products\/fat0005_2.jpg?v=1776459039","url":"https:\/\/khanscope.com\/en-fr\/products\/william-optics-cat71-redcat-71-mm-f-4-9-petzval-apo-refractor-t-c-71rd","provider":"Khan Scope Centre","version":"1.0","type":"link"}