[ATM] What can I do with this mirror?
vla at copper.net
Tue Jan 10 23:25:31 JST 2012
Not likely. The largest blur for given surface deviation is
produced by turned edge, and it would take 1 wave p-v
(0.55 microns) surface error for 95% zone to produce 0.13mm
blur diameter due to it with this mirror. That is 11 times the stated
surface accuracy of 500A. With 1% edge zone (3mm), the error would
be still twice this figure, but I doubt that small of a zone was
Any local irregularity closer to mirror center would require
larger nominal error to form a blur of this size. More likely
scenario is that the main contributor to the blur is the residual
figure error. I doubt that any 24-inch f/1.5 made for infrared
is exactly paraboloidal - even those made for the visible
range are not.
But, the figure can be either overcorrected, or undercorrected,
and this same blur would be produced by either -1.03 or -0.97 conic.
----- Original Message -----
From: Paul A. Valleli
To: vladimir sacek ; atm at atmlist.net
Sent: Tuesday, January 10, 2012 1:17 AM
Subject: Re: [ATM] What can I do with this mirror?
The blur circle was created from local zones and irregularities, not smooth spherical aberration.
The nominal Conic Constant would still be -1, a Paraboloid.
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