Re: [ATM] figuring 10 inch mirror

[hermit <hermit@outofoptions.org>]

Mark Holm wrote:

>Here is an interesting thing.  I tried "masking off" the outer 5
>millimeters of radius (10mm diameter) of Wayne's mirror in Sixtets  on
>the assumption that getting rid of that much of the turned edge would
>make a significant improvement in Strehl.  Surprise!
>
>http://www.atmlist.net/contrib/mdholm-at-telerama-dot-com/W_Hillard_7-22-05_Sixtests_Para_masked.jpg
>
>Although the turned edge is greatly reduced, the Strehl hardly budged.
>
>Perhaps we need to be more careful with the old advice to mask off
>turned edges.  Maybe it isn't the cure-all we have all assumed.
>
>  
>
Well, if you observe computer simulations, then don't mask the edge.  
If  you observe stars,  then my advice would be to mask the edge. ;-)

Ken
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