Re: ATM 11.2" F/2 Primary testing questions :)

["Dennis Nikitin" <ndenis@sarkor.com>]

----- Original Message -----
From: James Lerch <jlerch1@tampabay.rr.com>
To: <atm@shore.net>
Sent: Monday, December 31, 2001 7:39 PM
Subject: Re: ATM 11.2" F/2 Primary testing questions :)




<<<
Do I have to stop it down at the ROC, or can I do it at the FL?  Will doing
it at the FL, still allow of-axis light to make it the edge of the mirror?
>>>

Just in a few seconds after the moment when I had sent a message I realized
that I was wrong. I apologize. I meant that you should stop down the
aperture at the ROC to switch off coma. Unfortunately it won't work with the
parabolic primary. The spherical primary is needed to make my idea worthy.

>>>
The Piazzi-Smith lens you spoke of, is this some type of Coma-Correcter?  If
so what type of figure is it?  One of the hopes for this instrument, were to
avoid any lenses in the optical system, but if it's a must, then so be it ;)
<<<

The Piazzi-Smith lens is a Field Curvature Corrector but I think you don't
need it for astrometric purposes.

<<<
When you did your Spherical Null Test, Did you construct a Full size
spherical Lens, or did you use a sub-diameter lens and just move it around?
>>>

It was a sub-diameter spherical mirror........and I didn't move it around.
Try some tips on this test at
http://tlepage.home.mindspring.com/Waineo.html.
If you are interested I can email you formulas.

Dennis.