After 25 years, I finally have the dedicated field flattener for my 1996 vintage AstroPhysics Starfire EDF.  When I started to get serious about astrophotography, 20 years after getting this scope, I quickly realized that it needed a flattener, but there was no longer one that was made for these scopes, as the last production was in 2001. So I made do with a third party flattener, but could never get it quite right and certainly not round stars in all four corners. About 2 years ago, I heard that A-P was going to make some available and I got on The List. 

When I got The Call, I immediately got out the water-cooled credit card and also ordered the appropriate extensions and adapters which were fortunately in stock. George and I agreed on the necessary bits to come out to the nominal back focus spacing and it all arrived last Thursday. Miraculously , I only had to wait 48 hours for clear skies. Assembling everything just as planned, no measurements, I nervously waited while NINA went through all the necessary preamble and autufocus. When the first two minute sub came through, I nearly cried. 

Here is the first image with this new imaging accessory---3 hours of APS-c OSC data. The main point of this is to see how well the flattener works examining the edges of the frame, which has been cropped only to trim the dither edges. I haven't measured the spacing, which is supposed to be 86.4 mm by spec; the nominal spacing distance calculated by George and I based on A-P's dimensions and those specified by QHY for their components came to 86 mm. Based on results from that first night, I left things as they were for the next night. This image is the result of two nights' subs, 90x 120 seconds, part of a multi-target plan based on available target visibility and altitude. 

I will probably play with the spacing a bit; one millimeter more or less just to see how it changes. Admittedly, I am also using an upgraded mount, going from a CGEM to an iOptron CEM70, but the results that this new flattener/scope combination is delivering is very gratifying.