Sorry to continue the recent overflow of the chook images. This is a trial image from TSA102+STL11k combination with flattener.
My previous test with this combination with reducer produced about 18% curvature and stars in guide chip was comet like making internal guide chip unusable. I didnt expect this much curvature (I might be using wrong distance adapter!)
Last night was not a clear night but I wanted to see if the flattener would make things any better. Flattner reduced the curvature dramattically. CCD Inspector indicated curvature of 9% which can be improved a bit further i believe with some care to reduce tilt in X,Y axis. Drawbacks of using flattener with TSA102 is: Can't use CAA, matings are not threaded making the optical path pron to tilt.
Attached image is
Scope: TSA102 with flattner @F 7.84 Approx.
CCD: STL11k,
Image scale arcsec/pix: 2.3 approx
Exp: 7x 5min, Ha (Baader 7nm)
Self Guided: 4sec exp (my alignment wasn't that great)
