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ATM [Fwd: BOUNCE atm@shore.net: Admin request]



-- 
With Regards, Mel Bartels    Programmer/Analyst, and amateur astronomer
mailto: mbartels@efn.org     homepage: http://www.efn.org/~mbartels
How To Computerize A Dob:
http://zebu.uoregon.edu/~mbartels/altaz/altaz.html

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>From atm-owner  Sun Sep 22 19:20:08 1996
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Date: Sun, 22 Sep 1996 16:20:52 -0700
From: archer@meer.net (Archer Sully)
Message-Id: <199609222320.QAA00750@theo>
To: atm@shore.net
Subject: Help figuring Cassegrain mirror...


Hi,

I have a 12.5" f/3.96 mirror with a hole already drilled in it.  It
is around 70% corrected, so it might have been intended for a Dall-
Kirkham, but be that as it may, I want to turn it into a full paraboloid.
The figure on the mirror does seem to be better at the edge than at
the center.  I do have to polish around the hole, though, which I 
think will complicate matters.

I already have two laps made (thanks Mark!) one full size, and one 
8".  

So, does anyone have any suggestions for how to approach this figuring
job?  How is the presence of the hole affect the polishing process?
Am I likely to overcorrect, and spend the rest of my life trying to 
get back to a reasonable figure?  Should I be using a sub-diameter tool
most of the time, or the full size tool.

Any and all advice appreciated.  Confusion doesn't phase me ;-).

Archer Sully
email: archer@meer.net
home page: http://www.meer.net/~archer

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