|
Dunk,
There is a lot of good advice already on this thread.
But here is another consideration: perfect axial collimation of a fast Newtonian does NOT guarrantee absence of tilt of the image plane. The only condition where zero tilt is possible is that the focuser axis and the primary mirror axis intersect on the secondary mirror surface and the secondary long axis is at exactly 45degrees to both.
It is possible to achieve perfect axial collimation without the above condition being met.
With the size of your camera sensor, the problem is not as severe as with a large sensor, but you need to bear it in mind. I have seen distortions similar to what you have shown caused by tilt errors alone, although you probably have more than one problem here.
Mark
|