[ATM] What can I do with this mirror?

[vladimir sacek]

Paul,

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 
effectively tested.

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.

Vla

  ----- 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?


  Vladimir,
  The blur circle was created from local zones and irregularities, not smooth spherical aberration.
  The nominal Conic Constant would still be -1, a Paraboloid.