THE SOLAR ECLIPSE.
AN EFFICIENT VIEWING GLASS. For those who may be desirous of watching, without injury to their eyes, what little it is possible to see here of next Thursday’s solar eclipse, the Commonwealth Government Astronomer’s recipe for the preparation of “an excellent viewing glass’ will be of interest. It is as follows:— Take any unexposed photographic immerse it any suitable developing solution, in the dark room, for about 10 seconds, then turn on a fairly strong light for about half a minute, whilst the plate is still being developed. Extinguish the light and continue development until the plate is deep black. Then fix and wash as usual. The final product should be so dense that an ordinary incandescent lamp is almost invisible through it, and there should not be the smallest effect of glare when observing the sun. “I believe,” he adds, “that any plate will do, but the above figures refer to an Austral process plate, and an ordinary house electric light at a distance of about four or five feet. If a number of glasses are required use whole plates, and afterwards cut them into strips of about 3xl inches. Each plate will make 16 strips.
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Bibliographic details
Hawke's Bay Tribune, Volume XII, Issue 235, 18 September 1922, Page 5
Word Count
200THE SOLAR ECLIPSE. Hawke's Bay Tribune, Volume XII, Issue 235, 18 September 1922, Page 5
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