Quote:
Originally Posted by bojan
Why don't you have a look at some ATM site and do it yourself?
It is quite easy thing to do (to determine your mirror is bad I mean) by using a point light source and edge (Fucault test, easy and widely used).
And of course, visual test on bright star (with good eyepiece) or difficult double should be enough to satisfy your first levels of curiosity.....
These tests, performed by others are not cheap, to do them may cost you more than new mirror (from GSO)
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Yes, it's quite easy to check if the mirror is
bad--turned edge, rough surface, zones etc. However, with focal ratios of f5 and faster, testing to see if the mirror is
good (ie how close the mirror is to a perfect paraboloid) is quite tricky if you haven't ever done it before. The star test is probably your best bet. See "Star Testing Astronomical Telescopes" by H R Suiter. Bintel sell it for $69--it's well worth the price.
Geoff