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Re: Increasing primary and secondary mirror quality

Subject: Re: Increasing primary and secondary mirror quality
From: starburst
Date: Tue, 02 May 2006 16:37:57 -0500
Newsgroups: sci.astro.amateur

Also, what are some easy home
quality checks that I can perform?

Start splitting equal doubles from 0.7" down to 0.4". If it never fails
splitting them then your scope is OK.

Andrea T.

Caution on this, though. Make sure that the night you choose to do the check has really good seeing. Poor seeing will make it appear that a decent mirror is a piece of junk, so be careful.

You can always rig up a test bench using a homemade foucault tester. Lot's of info on these online - if you go this route I'd recommend making a "slitless" tester. They're easy enough to make, though you will need to practice with it a little while before you accept the data you're getting. It will give you a rough idea of your mirror's quality and you don't have to wait for a night of outstanding seeing, which in some parts of the country never seems to come along.

But the best way to test your mirror is via a star test. That will tell you the most. For info on this, take a look at Suiter's book on star testing.

Don't assume that your mirror is junk. Good ones get through, too.


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