Quote:
Originally Posted by gregbradley
There you go. If you had pinched optics you should be able to see this effect visually and it would appear on every image.
If its a guiding issue it looks like there must be a large periodic error spike at some point in the worm cycle.
Have you sat and watched a whole exposure's worth of 1 exposure with these stars? Was there a sudden spike in errors at one point?
A triangular shape like that is unusual in my experience with tracking. Normally if I get a bad spike it looks like double stars everywhere or a bad elongation in one direction but a triangle.
It does look a bit like coma as well. Are you using a corrector/reducer? Perhaps its at the wrong spacing. Usually Tak is either 87mm or 120 odd mm. There is a list of metal back distances for Tak scopes at Anacortes.
Greg.
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I watched the guide star for a little while and there was a bit of moving around but it looked fairly uniform. It was also a bit windy and I think that accounts for some of the more pronounced streaks on some of the other exposures.
I have no corrector/reducer yet, I'm planned on getting a corrector but I want to make sure everything is working without it first.
I hope it is just guiding, next clear night I'll take my time with a good polar alignment and make sure balance etc is spot on, at least then I can either fix or rule out guiding as the problem.
Thanks for your help Greg.