Posts Made By: Paul Starr

August 2, 2006 07:58 PM Forum: Eyepieces

Burgess Optics TMB PLanetary Review

Posted By Paul Starr

Floyd,
As usual, a very well done and informative review. Thanks for taking the time to share it.
Paul

June 21, 2007 09:42 PM Forum: Eyepieces

About contrast

Posted By Paul Starr

Dang it Floyd, now I had to go and order one.

Paul

July 17, 2007 08:58 PM Forum: Reflectors

Galaxy/Royce/Discovery/?

Posted By Paul Starr

Of the three you mention, I would pick Royce. I don't know what Galaxy mirrors are like today but in the past, 1990, They listed their mirrors as 1/20th wave, with plenty of hype on their web site and when one was purchased and tested by Sky & Tel., it turned out to be 1/2.8 wave. I would also give Stevens Optical a look. He also makes some fine mirrors.

Paul

http://www.stevensoptical.com/

July 15, 2008 11:29 PM Forum: Equipment Talk

Mirror refigure

Posted By Paul Starr

Try here. http://www.opticwavelabs.com/refiguring.html

March 9, 2009 04:43 PM Forum: Equipment Talk

Laser collimator

Posted By Paul Starr

The Hotech collimator is very good. I have one and like it very much.
http://www.hotechusa.com/collimator.html

April 11, 2009 03:42 PM Forum: Equipment Talk

Recent Interferometic test results

Posted By Paul Starr

Unfotunatly, in the case of the C-9.25, even with perfect optics, the overall strehl won't be more than 0.71 with a 40% central obstruction. 0.63 if the system is 1/4 wave. This is per Suiter's book on star testing.

April 14, 2009 12:28 PM Forum: Equipment Talk

Guess what this is?

Posted By Paul Starr

A lit up circle with a dark center.

April 15, 2009 06:47 PM Forum: Equipment Talk

Shipping scratches on primary is recoating necessa

Posted By Paul Starr

Yours don't sound to bad. I shipped a 12" once that I went through great lengths to pack correctly. When the coater shipped it back, they trough my packaging away and left the mirror face down in the box on some soft paper. The mirror was not tight in the box and it must have rubbed back and forth with the motion of the truck. The paper was full of sparkly flakes of coating. The mirror under a tester showed a shadow rubbed permanently in the glass where it rubbed. The coater said sorry about that but all we can do is re-coat it for you. I had to get it re-figured. It is very important to have the mirror tight in the shipping box.

August 25, 2009 01:20 AM Forum: Chinese Optics Imports

November 1, 2009 12:09 AM Forum: Equipment Talk

1968 Optical Craftsmen: pinhole & foucault

Posted By Paul Starr

I recently sent a mirror to a noted custom mirror maker for evaluation and possible refiguring. The mirror had a good figure but he said there were three, what looked like fingerprints that showed up in the Foucault test. He thought the original maker touched the surface and the glass raised due to the heat from his fingers. When put back on the tool, the raised areas then became holes after the mirror was figured and had cooled down. He was sure the problem was ground in the glass. When the coating was removed, the fingerprints were gone. Problems that look permanent can sometimes be in the coating.