I have the Astro-Tech 130mm f/7 EDT refractor and want to use it with a full-frame sensor. The scope has a very nice 2.5" focuser, but the Astro-Tech field flattener slides into a 2 inch tube which will at the very least cause lots of vignetting - and at the worst will chop off the corners of the image. Does anyone know of a field flattener with a larger optical path?
Field Flattener for a 2.5" Focuser
Posted 13 March 2018 - 05:22 PM
TS has a 3" FF/FR. Their 2.5" unit is almost exactly the same (exactly same optical formula, just different camera spacing required) that Astro-Tech sells for the AT130EDT.
Edited by fmeschia, 13 March 2018 - 05:24 PM.
Posted 13 March 2018 - 10:42 PM
Do you mean ES? Explore Scientific? Their 3" unit is also an 0.7 focal reducer, and I'd prefer a straight flattener. Also, its not clear that their adapters will mate with the threads on the 2.5" focuser.
Posted 14 March 2018 - 07:49 PM
This is one of the things it's best to sort out before buying a scope. You might ask in one of the imaging forums and see if there is a best fit out there.