Joe I wouldn't touch it with the cloth. I would use a blower bulb to blow dust off. If that doesn't clean it well enough see http://www.optcorp.com/pdf/ASOCleaningGuide.pdf As they note: cleaning coated optical surfaces is the single most damaging action that will be done to them, short of actual physical damage or breakage. No matter how careful, how delicate, nor what cleaning solution is used.....every time cleaned will result in a microscopically-reduced optical performance than before cleaning. So only clean if absolutely necessary. If you don't want to make up your own solution you can buy the Arkansas Sky Observatory cleaning kit, Doc Clay's Cleaning Kit, at http://www.optcorp.com/product.aspx?pid=1952&kw=cleaning&st=2 -----Original Message----- From: utah-astronomy-bounces+djcolton=piol.com@mailman.xmission.com [mailto:utah-astronomy-bounces+djcolton=piol.com@mailman.xmission.com] On Behalf Of Joe Bauman Sent: Monday, May 07, 2007 12:51 PM To: Utah Astronomy Subject: [Utah-astronomy] dirty lens My outermost lens is pretty dusty on my SCT 12". (Sorry, I can't remember what it's called -- is it a corrector plate?) Would it harm my telescope to gently dust it off with a specialty cloth used for computer screens? Any suggestions? Many thanks, Joe _______________________________________________ Utah-Astronomy mailing list Utah-Astronomy@mailman.xmission.com http://mailman.xmission.com/cgi-bin/mailman/listinfo/utah-astronomy Visit the Photo Gallery: http://www.utahastronomy.com