I just recently obtained a William Optics Redcat 51. I have loved everything about it so far, except I can't get a flat field. I have achieved a backfocus of 55 mm on it with my ZWO 1600 MM (camera+electronic filter wheel + 16.5 mm spacer), but I notice that the image still isn't flat. Does anyone have any idea why this might be the case? The scope is supposed to not require a field flattener. I have attached a recent image I took as an example.
I've been hunting down every image I can taken with the Redcat and haven't found any perfect images in terms of the field yet. Coma has been mild to severe in most of them.
Will this allow you to return it?
Same thing with my EON 85mm, but the way they word it means they have a loophole in my case :
What does this mean for you, the consumer? With its two fluoro-crown ED glass elements and fully multi-coated optics, the Orion EON 85mm ED-X2 refractor provides superior correction of chromatic and spherical aberrations. By suppressing these aberrations so effectively, this triplet "apo" telescope produces impeccable visual views and razor-sharp astrophotos without any fringing or loss of clarity.
But this thread is not about my Eon. If a manufacturer promotes a flat field, then they really need to deliver one. in my case I think the adverting was misleading but when I do an astrobin search of redcat I find quite a few images where it would take a discerning eye to catch the coma:
Edited by Ballyhoo, 14 July 2019 - 02:31 PM.