Re: Re[2]: ATM 10in. Mirror--Star Test ?'s

[Brand <huntb@ucs.orst.edu>]

> 2) Yes - this is the ultimate test.  Reading the errors can be tricky if 
> multiple errors are present - however it is best to do general 
[snip]
> sphere and parabola when done polishing, making star testing interpretation
> easier.

John,

What do you guys mean about the star test? I'm new at this and don't know 
how to set it up, I tried placing an unsilvered mirror at my feet and 
then looking at Vega (the only bright "star" at the time) and looked at 
the image at the focus. It illuminated the entire surface with no 
shadows, but this didn't make sense to me because I knew it was a 
hyperbola (4x) and this is my first mirror so I just didn't know if "test" 
made sense. :)
If I do this and it is a paraboloid, should I see shadows at the focus? 
Should I use a higher magnitude star, or is your guys star test different 
then mine?
The star test stuff in the books that I have (Texereau, Howard, and 
Blackie or something like that [library books]) show the star test to be 
done with an high powered eyepiece and a silvered surface -- i think.

Please unconfuse me, Thanks.

__________________________________________________________________
Brand Hunt                 Email: huntb@ucs.orst.edu
Computer Consultant,       WWW  : http://www.engr.orst.edu/~huntbr
Information Services       Phone: (541) 737-9375

       "My signature is over the recommended four lines."