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Lumicon Oxygen III line band filter for Schmidt-Cassegrain visual backs | |
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| This visual back Oxygen III line filter threads onto the 2" rear cell of 5" and larger Celestron Schmidt-Cassegrain telescopes and 7" and larger Meade Schmidt- and Maksutov-Cassegrains. It duplicates the 2" rear cell threads of those telescopes, allowing all visual accessories to be attached securely to the filter instead of directly to the scope. It allows medium to long focal length eyepieces to be changed quickly in a star diagonal without having to exchange the light pollution filter from one eyepiece to another. It has a very narrow 110 Ångstrom passband with excellent transmission of the nebula emission lines of doubly ionized oxygen at 4959Å and 5007Å. The very narrow passband gives two to three times the contrast of a standard narrowband filter for observing brighter nebulas like M17 and M27 from heavily light-polluted city locations. It is excellent for visually observing very faint planetary and gaseous nebulas (such as M76 and Barnard’s Loop in Orion) that are normally invisible without a filter from mildly to moderately light-polluted sites. The narrow passband and high Oxygen III transmission combine to make emission and planetary nebulas stand out crisply against the blackness of space. The filter is not designed for astrophotography or for observing reflection nebulas. The filter comes with individually-measured transmission data. The filter is best with medium to large aperture scopes (6" and larger). Enter your telescope focal ratio in the formula box to the right to see what focal length eyepieces will work best with this filter.
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Terms of Sale | PRIVACY POLICY 7/1/2004 | Fine Print
Toll-Free Telephone Astronomics: 800-422-7876; Christophers, Ltd.: 800-356-6603
Alternate Telephone: 405-364-0858 24 Hour Fax Line: 405-447-3337
Telephone Hours: Monday-Friday 8 AM - 9 PM CST
Saturday Noon - 5 PM CST
Store Hours: Monday-Friday 9 AM - 5 PM CST
Saturday Noon - 5 PM CST
Astronomics / Christophers, Ltd.
680 S.W. 24th Ave.
Norman, OK, 73069
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