Quote:
Originally Posted by toryglen-boy
So, i get bad coma on the F5 scope when taking pictures, and i use an MPCC, although i found it tricky to get the spacing right, so i ordered the QHY8 MPCC back focus matched adaptor from Peter Tan, and although its machined very nicely and fits, but i still get coma, even though i am using the right spacing (55mm)
Also, i get really bad reflections of the colimation marker in the primary when i use the MPCC, and i mean REALLY bad, any brightish stars in the image, produce a red doughnut, right next to it.
Have any of our QHY8 and MPCC users managed to do anything about getting the right spacing, and getting rid of reflections?
thanks
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Duncan, it sounds as though it is mainly a collimation issue but in order to at least isolate the source of the problem, see if you can borrow a DSLR from someone and take some shots with that (leaving everything else in place). It may show you that the reflections either are, or are ot within the QHY8. That's a start.
Peter