{"product_id":"takahashi-flattener-1-01x-for-fsq-85edx","title":"Takahashi Flattener 1.01x for FSQ-85EDX","description":"\u003ch3\u003e\u003cstrong\u003eProduct Overview\u003c\/strong\u003e\u003c\/h3\u003e\u003cp\u003eThis flattener extends the FSQ-85EDX's corrected field to a 44 mm image circle — enough to cover a full-frame sensor's 43.3 mm diagonal completely. At 1.01x it changes focal length only fractionally, from 450 mm (f\/5.3) to 455 mm (f\/5.4), so this is a corrector rather than a focal-length changer.\u003c\/p\u003e\u003ch3\u003e\u003cstrong\u003eWho It's For\u003c\/strong\u003e\u003c\/h3\u003e\u003cp\u003eThis is what you need if you image with an FSQ-85EDX on a full-frame sensor and want flat, round stars into the corners of the frame, not just the APS-C centre.\u003c\/p\u003e\u003ch3\u003e\u003cstrong\u003eOptical \/ Mechanical Design\u003c\/strong\u003e\u003c\/h3\u003e\u003cp\u003eThe FSQ-85EDX's petzval design is already well corrected across a smaller field; this flattener extends that correction out to a 44 mm circle by adding the last small amount of field curvature correction the native optical path doesn't reach on its own. The 1.01x factor is nearly unity — the flattener is doing geometry, not speed — which is why the focal length shift is so small: 450 mm becomes 455 mm, f\/5.3 becomes f\/5.4. Backfocus behind the flattener is 36 mm, with a 56.2 mm metal back distance from the telescope's own reference point, and the front face takes M58 filters directly.\u003c\/p\u003e\u003ch3\u003e\u003cstrong\u003eRecommended Uses\u003c\/strong\u003e\u003c\/h3\u003e\u003cul\u003e\n\u003cli\u003e\n\u003cstrong\u003eFull-frame deep-sky imaging on the FSQ-85EDX\u003c\/strong\u003e where the native field falls short of covering the sensor's corners.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eWide-field mosaics\u003c\/strong\u003e where consistent corner star shape across panels matters.\u003c\/li\u003e\n\u003c\/ul\u003e\u003ch3\u003e\u003cstrong\u003eCompatibility and Accessory Notes\u003c\/strong\u003e\u003c\/h3\u003e\u003cp\u003eThe flattener threads M72 x 1.0 male into the telescope side and presents M54 x 0.75 female to your camera adapter, with 36 mm of backfocus to the sensor. The front face's female thread accepts M58 filters directly, ahead of the flattener glass. If you're building out a full imaging train and want the spacer stack confirmed to the 36 mm figure, send us your camera and filter setup and we will work it out with you. See the \u003ca href=\"\/pages\/takahashi-back-focus-guide\"\u003eTakahashi Back Focus Guide\u003c\/a\u003e for the FSQ-85EDX's full published figures.\u003c\/p\u003e\u003ch3\u003e\u003cstrong\u003eGood to Know Before You Order\u003c\/strong\u003e\u003c\/h3\u003e\u003cul\u003e\n\u003cli\u003e\n\u003cstrong\u003eThis is a photographic corrector.\u003c\/strong\u003e It has no application in a visual train with an eyepiece.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eBackfocus is 36 mm from the rear thread.\u003c\/strong\u003e Corner star shape follows how closely your adapter stack hits that figure — send us your setup and we will confirm the spacer stack before you order.\u003c\/li\u003e\n\u003c\/ul\u003e\u003ch3\u003e\u003cstrong\u003eFrequently Asked Questions\u003c\/strong\u003e\u003c\/h3\u003e\u003cp\u003e\u003cstrong\u003eIs it difficult to set up?\u003c\/strong\u003e\u003c\/p\u003e\u003cp\u003eIt threads directly onto the FSQ-85EDX at M72 x 1.0. The work is in hitting the 36 mm backfocus on the camera side, which is arithmetic — add up your adapter, filter drawer and spacers, and send us the numbers if you want them checked.\u003c\/p\u003e\u003cp\u003e\u003cstrong\u003eDoes it change my focal length?\u003c\/strong\u003e\u003c\/p\u003e\u003cp\u003eOnly slightly — 450 mm at f\/5.3 becomes 455 mm at f\/5.4. It's a flattener, not a reducer.\u003c\/p\u003e\u003cp\u003e\u003cstrong\u003eWill it cover a full-frame sensor?\u003c\/strong\u003e\u003c\/p\u003e\u003cp\u003eYes — the 44 mm corrected circle covers a full-frame diagonal of 43.3 mm.\u003c\/p\u003e\u003cp\u003e\u003cstrong\u003eCan I fit filters directly to it?\u003c\/strong\u003e\u003c\/p\u003e\u003cp\u003eYes — the front face takes M58 filters ahead of the flattener glass.\u003c\/p\u003e\u003ch3\u003e\u003cstrong\u003eBottom Line\u003c\/strong\u003e\u003c\/h3\u003e\u003cp\u003eIn short: a 200 g, 1.01x flattener that gives the FSQ-85EDX a 44 mm corrected circle for full-frame sensors, at 36 mm of backfocus — send us your camera and filter setup and we'll confirm the spacer stack with you.\u003c\/p\u003e","brand":"Takahashi","offers":[{"title":"Default Title","offer_id":54047112626287,"sku":"TAK-TKA37582","price":351.78,"currency_code":"CAD","in_stock":false}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0686\/0049\/6239\/files\/TKA37582_1.jpg?v=1786914068","url":"https:\/\/ontariotelescope.com\/products\/takahashi-flattener-1-01x-for-fsq-85edx","provider":"Ontario Telescope and Accessories","version":"1.0","type":"link"}