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| A refractor telescope with a two to four lens optical system that uses one or more elements of costly ED (Extra-low Dispersion) or SD (Special Dispersion) glass and/or calcium fluorite crystal to virtually eliminate chromatic aberration. Technically, any lens system that is corrected for spherical aberration at two wavelengths, or colors of light, and for chromatic aberration at three. |
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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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