From: "James Lerch" 
To: "ATM List" , 
Reply-To: "James Lerch" 


Greetings All,

I think I've got this simulated star test code nearly complete (Of course
the accuracy and usefulness of such a thing is probably questionable at
best)

In effort to see if the code was producing any type of useful results, I
compared FigureXP to Aberrator Version 3.  Here's the comparison:

http://lerch.no-ip.com/atm/Fig_V_ab.jpg (144 KB)

In the above image, FigureXP results are the top row of images, and
Aberrator is the bottom row.  From left to right of each is:

#1 Intra focus 0.13mm
#2 Ideal mirror 0.13mm defocused (intra/extra should be the same)
#3 Extra focus 0.13mm

Both sets of images had a 33% obstruction.  The FigureXP images were based
on this surface error plot:
http://lerch.no-ip.com/atm/FIg_John.jpg (278 KB)

The Aberrator images were based on this:
http://lerch.no-ip.com/atm/Aberator.jpg (226 KB)

Fortunately the results seem pretty close (difference mostly being
brightness/contrast related).

Aberrator seems to like quoting defocus in "waves", so anyone
have a formula to go from mm defocus to waves defocused?  I've been trying,
and I know the result is a function of the Focal Ratio, I just can't figure
it out :(

Take Care,
James Lerch
http://lerch.no-ip.com/atm (My telescope construction,testing, and coating site)

--- BBBS/NT v4.00 MP