Quote:
Originally Posted by Startrek
Ryan
I think this maybe overcomplicating things by trying to analyse my issues to deeply, it’s an issue which has multiple fronts and I’ve tackled each one by trial and error with some success
And yes I did remove all my spacers last night to leave the distance at 55mm which has helped a lot , whereas a week before , I had spacers of 1.5mm and my stars were fine ( no answer at all for that scenario )
My stars are better now but still slightly off shaped on the far left hand side
Could be the coma corrector
Could be the primary mirror ( there is a slight chip on one side on the edge )
Could be the primary mirror cell holder or adjusting screws
Could be the focuser
Could be the camera
Could be ...... many things
What I can’t resolve is that a week ago my stars were fine and somehow they changed without me touching anything on the rig and it’s equipment
I don’t think my experience is of any use to others as there are so many variables and you have to work through them one at a time
No one shoe fits all with optical problems ( only the blatantly obvious)
Thanks as always for enquiring
Cheers
Martin
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So this reply was based on the fact that you said that you had “ resolved “ your problem. The “ penny had dropped “ and the solution was the coma corrector spacing. I don’t feel like a very basic explanation of how coma correction works is over complicating things. I would suggest that even a low level understanding of it is required when imaging with a Newtonian telescope. In your post even sounded like you were surprised that f/6 would require different spacing than f/5. That’s why I felt the need to write a short over view of the consequences of over correction. The target audience being other far less experienced imagers that may read this post and rely on its contents to resolve problems they may be experiencing. I just feel that you aught to be careful when stating you’ve corrected a problem and what your findings were if you either haven’t fully corrected the problem or haven’t really evaluated what happened. You’re now saying that the problem arose a week ago having changed nothing on your setup and yet you also claim that it was because you had gone from your south coast f/5 to your sydney f/6..... and might I add 8” to 6” scope..... that sounds like quite a significant change of equipment. If that is not the case and you had perfect stars one night on the f/6 and then all your problems on the same f/6 then how is even possible that corrector spacing was the solution ?
Iterative processes are often used to tune out solutions to complex problems of which there are myriad in this hobby. They generally start with a basic understanding. This is an understanding that you very often provide to beginners in the form of your many process PDFs. A lot of people read your posts and take advice from them. If you are going to post solutions then you have a responsibility to make sure they are correct.
Cheers
Ryan