Thread: Squashed stars
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Old 23-09-2020, 07:12 AM
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multiweb (Marc)
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Join Date: Oct 2007
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Quote:
Originally Posted by BeardFace View Post
Well that's good to hear, thanks! It wasn't guided but I wouldn't be surprised if it was off balanced in the dec.

Is it possible that the pinch would come from tightening the primary down too hard?
When you get a trefoil, three points at 120 degrees it usually points to stress in a mirror holder. So if you have three points behind your secondary (collimation screws) or three points in your primary mirror cell then yes it could be one of these two. What happens when temperature changes glass contracts or expands. If it's already tight at 20c let's say when you're up and about and your scope goes down to 5c then the glass has nowhere to go, "no room to breathe". The pinch shows in your stars. Every scope has the same issues. Just loosen up the screws just enough and the pattern will go. Or you can use a crumple zone. A thin piece of cork will give enough way rather than glass direct on alu.
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