I was just going to open a discussion on this subject to seek the advice of Master Roland.
I received this week the focuser 3.5 to upgrade my AP130GT, in order to mount the QuadTCC on it.
I did 2 nights of testing with an ASI6200 and I can't manage to get perfectly picky stars in the corners.
I did about ten assemblies with different distances to 0.3mm and here is the best result I get.
I don't know if this is normal, if I have reached the maximum of what the Ap130/Quad combo can give. Or if I can still improve?
I had to adjust a slight tilt, and when I add or remove 0.5mm the field curvature increases.
For the settings I use CCDInspectore and ASTAP.
Maybe I am too demanding? The stars in the corners are not perfectly round but rather triangular.
I specify that before that I had mounted the QuadTCC on an LZOS 152F8, I managed to set the backfocus perfectly and I get perfect and round stars in the corners.
Also I find it strange that the ideal distance I found is 100.6mm when it is supposed to be 103.8 + 1mm for the spacer of my filters.
Am I missing something?
Sorry to ask questions more than I answer Sebastien
To the pleasure,