Printer Friendly

Planetarium workshop.

I was very interested in the photograph of Allyn Thompson in the November issue (page 20). I believe he was standing with his telescope on the ground level of the planetarium in New York City.

In the late 1950s I enrolled in the night course for telescope-mirror making at this planetarium. I commuted once a week from Montclair, N.J. In spite of my efforts, the course ended before I was ready to figure my 6-inch mirror into a parabolic shape (the difficult part!). They were kind enough to finish it for me. I picked the mirror up later and had it aluminized.

Several years ago I tested the mirror using the Foucault method described in Thompson's book, Make Your Own Telescope. It was right on.

Art Siegel

New Hartford, Connecticut

COPYRIGHT 2012 All rights reserved. This copyrighted material is duplicated by arrangement with Gale and may not be redistributed in any form without written permission from Sky & Telescope Media, LLC.
No portion of this article can be reproduced without the express written permission from the copyright holder.
Copyright 2012 Gale, Cengage Learning. All rights reserved.

Article Details
Printer friendly Cite/link Email Feedback
Title Annotation:Letters
Author:Siegel, Art
Publication:Sky & Telescope
Article Type:Letter to the editor
Date:Mar 1, 2012
Previous Article:Visual observers' creds.
Next Article:Look to the nitrogen.

Terms of use | Privacy policy | Copyright © 2021 Farlex, Inc. | Feedback | For webmasters