261![The Use of Astronomical Filters One of the puzzles of visual astronomy that many beginning amateur astronomers get caught up in is the use of filters. Which ones to purchase, and which ones are useful for what types of observing are the most The Use of Astronomical Filters One of the puzzles of visual astronomy that many beginning amateur astronomers get caught up in is the use of filters. Which ones to purchase, and which ones are useful for what types of observing are the most](https://www.pdfsearch.io/img/f710d2eac78ca0c53d8d2adb6df2221d.jpg) | Add to Reading ListSource URL: sas-sky.orgLanguage: English - Date: 2012-04-06 13:03:58
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262![1 W. F. Denning - The Doyen of Amateur Astronomers. 1 W. F. Denning - The Doyen of Amateur Astronomers.](https://www.pdfsearch.io/img/6a2f9d704becbf844ba4c566410ae223.jpg) | Add to Reading ListSource URL: hyperion.cc.uregina.caLanguage: English - Date: 2003-07-24 14:16:44
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263![](https://www.pdfsearch.io/img/3a9ba68b3a2ac7fa138aa45323a3da91.jpg) | Add to Reading ListSource URL: www.nightlife.demon.co.ukLanguage: English - Date: 2005-02-28 15:53:37
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264![](https://www.pdfsearch.io/img/71cf87a1145af1ef783de359de686dee.jpg) | Add to Reading ListSource URL: www.alpo-astronomy.orgLanguage: English - Date: 2008-06-15 21:23:34
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265![Untitled Untitled](https://www.pdfsearch.io/img/4d0c600178ee52cc0f274532cb88129e.jpg) | Add to Reading ListSource URL: alpo-astronomy.orgLanguage: English - Date: 2008-06-15 21:20:57
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266![](https://www.pdfsearch.io/img/3a8d9e9db2b0340778566d295331b753.jpg) | Add to Reading ListSource URL: arxiv.orgLanguage: English - Date: 2009-05-28 18:31:04
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