Re: [ATM] spherical mirrors

["Steven L. Dodds" <steve@pcmw.net>]

----- Original Message ----- 
From: "Jay Kirkland" <jaykirk2@compusmart.ab.ca>
To: <atm@atmlist.net>
Sent: Saturday, January 22, 2005 7:46 PM
Subject: [ATM] spherical mirrors


>A table in Star Ware gives the following values. They are based on a 
>formula derived by Couder  for minimum fl that the mirror may be left 
>spherical:
> 3" = f 6.3, 4.5" = f7.3, 6" = f8.2, 8" = f9.0 and 10" = f 9.6. As you can 
> see, the fl increases with mirror size. However, I have just read 
> somewhere (and trying to find exactly where is driving me nuts), possibly 
> on this list, that these numbers are now considered way too optimistic, 
> and that the fl for a 6", say,  should be somewhere in the f10 to f12 
> range for truly good performance. If I can find that source here, I'll 
> re-post.
>
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> ATM mailing list http://www.atmlist.net/

I think these numbers are wrong. I ran them and they come out to .25 waves 
surface spherical abberation (.5 waves wavefront) it should be .25 waves on 
the wavefront to meet the Raleigh critierion.

it should be:

4" f/8.5
6" f/9.8
8" f/10.75
10" f/11.5

Steve





Steven L. Dodds
Nova Optical Systems
http://www.nova-optical.com
> 

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