RE: [ATM] Is There a Difference

["Richard Schwartz" <richas@earthlink.net>]

In optics we have the Ray-Lee criterion:   if the optical path difference is
less that 1/4 wave, the optical system is indistinguishable from perfect.
However, for many years, one well known telescope manufacturer claimed that
their small aperture scopes were better than larger ones because their
optical quality was BETTER than perfect.   

The mirror blanks I make are all good to 1/10 wave without any grinding or
polishing at all.  However, for light at shorter wavelengths than 2cm, their
performance may be degraded somewhat.

. . . Richard


-----Original Message-----
From: atm-bounces@atmlist.net [mailto:atm-bounces@atmlist.net] On Behalf Of
hermit
Sent: Wednesday, July 06, 2005 4:44 PM
Cc: atm@atmlist.net
Subject: Re: [ATM] Re: ATM Digest, Vol 19, Issue 8

jeff newsom wrote:

>  My lack of experience will no doubt show thru with this question,but I've
been told by that "well known astronomer guy" mentioned not to long ago on
these pages, that it's  difficult to tell the difference between a 1/8 wave
mirror and say a 1/16 wave or 1/20 wave(assuming all other factors in the
optical path are essentially perfect, a fantasty situation I'm sure.) What
say the masses? Let the salvo begin! Thanks--Jeff Newsom
>
>  
>
Please don't reply to the digest form.  It rebroadcasts all of the 
previous messages.

That said, how good an optic is  needed depends on the observer and 
their abilities.  That is perhaps why the "well known astronomer guy" 
produces optics that some here have reported to be lacking.

Ken
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