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IN THIS magazine last June Professor Russell described the Schmidt telescope- or camera, to speak more exactly, since it cannot be used to advantage as a visual instrument-and this present month with his article (pages 248-249) we have reproduced photographs, one celestial, the other terrestrial, ta..
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SETTING CIRCLES ARE GRADUATED rings that enable the astronomer to set his telescope exactly on desired celestial objects, from coordinates given in published lists, without even looking at the sky. Since these circles are a luxury, they are not usually fitted to the beginner's telescope. This is goo..
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ONE NIGHT last summer James T. Barkelew and Byron L. Graves of Los Angeles, with Russell W. Porter of Pasadena, went off on a jaunt in the California hills, taking along with them Barkelew's small reflecting telescope. Porter was so impressed by a slow-motion wrinkle which Barkelew has applied to a ..
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IF A MECHANISM DOES its intended work, and satisfies its owner, it is a success. A fine telescope drive, with gears and fancy trimmings (machine work), is a pretty thing to have, but also is complex and costly. A good telescope drive (Figure 1), innocent of sex appeal but which gits thar just the sa..
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IN 1931, Daniel E. McGuire, a Shadyside, Ohio, farm lad then 17, hit on the use of a slit in place of a pinhole in the telescope mirror maker's Foucault knife-edge test and for this his name has been in the book "Amateur Telescope Making" (page 380) since the edition of 1933. Later, McGuire became a..
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IN THE LAST stages of telescope mirror grinding the pencil mark test is sometimes resorted to in an endeavor to bring the mirror and its mating tool to full spherical contact, preparatory to polishing. This test is described in "Amateur Telescope Making," page 288, thus: "As finer sizes are used, ma..
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THIS month we shall devote most of our space to an interesting letter from Mr. Vard B. Wallace, a chemist, Box 874, Long Beach, California, and wind up with a brief description of two newly discovered methods of grinding and polishing mirrors. Mr. Wallace's communication follows:"Editor Amateur Tele..
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MANY OF the advances in practical optics and telescope making have been made by amateurs. Such an advance is a very much needed test for convex optical surfaces, devised by J. H. King of Amityville, New York. At our request, Mr. King has prepared a description of his test, which is reproduced below,..
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HERE IS A whole new chapter of interesting material written by Russell W. Porter of the California Institute of Technology, with an accompanying batch of his own drawings. He entitles the story "More Small Lens Wrinkles." and intends it as a follow-up to his chapter on eyepiece making, contained in ..
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