RE: [ATM] 6-point cell?

["Cord Scholz" <cord@astro-image.com>]

Rob, I recently went through the same decision process. First I had glued my
1.25" thick 12.5" directly to a support plate (1.5" thick carbon-honeycomb
sandwich), the result was bad astigmatism. Now I have glued the mirror to 3
pivoting bars which are held in place by ball bearings. In this
configuration I can't detect any astigmatism. Note that I don't even use an
edge support and I don't think that it is necessary for mirrors of this size
unless they're unusually heavy.

Regards,
Cord Scholz
www.astro-image.com

   

-----Original Message-----
From: atm-bounces@atmlist.net [mailto:atm-bounces@atmlist.net] On Behalf Of
me
Sent: Thursday, February 10, 2005 1:42 AM
To: atm@atmlist.net
Subject: [ATM] 6-point cell?

Hi,
 I've got a 10" f/6 1.6" thick mirror which I am making a cell for. I am
planning a 6-point cell, using RTV.
I am thinking of one of two paths:

1. attach mirror directly to support plate with 6 blobs of RTV. 

2. have 3 pivoting bars, each with 2 pads.  RTV the mirror to these pads.
The bars would attach to the plate with swivel joints.


  In either case, I would use edge supports .... either RTV or multiple
points.  The pivoting bar aproach would be more work.  Does it have any
advantage?

  Any opinions on this?

Cheers,
Rob

_______________________________________________
ATM mailing list http://www.atmlist.net/

_______________________________________________
ATM mailing list http://www.atmlist.net/