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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

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Title Annotation:Letters
Author:Siegel, Art
Publication:Sky & Telescope
Article Type:Letter to the editor
Date:Mar 1, 2012
Words:131
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