Joe, Blowing it off is the safest thing to do. If you've got crud on the inside of the corrector or on the secondary, you can tape a plastic soda straw to the end of a blow bulb (use the type of straw that has the bending zone). You can then insert this through the mirror cell (where the diagonal goes in), and carefully maneuver the end of the straw into place under the corrector. Unless you've got negative pressure near the mirror cell, this still means that the dust is only displaced inside the scope, but with a little luck it will land on the inside of the tube. Of course, if it lands on the mirror, you haven't really improved anything. I successfully used this technique to get a nasty blob off the secondary in my 5". But as most others have said, little tiny specks of dust won't really cause a lot of harm. Michael -----Original Message----- From: "Don J. Colton" <djcolton@piol.com> Sent: Apr 13, 2004 9:16 AM To: Utah Astronomy <utah-astronomy@mailman.xmission.com> Subject: RE: [Utah-astronomy] seeking advice Hi Joe Just blow it off with a hand bulb blower like they sell at camera stores. Do not use compressed air. Do not use any liquids they just make it worse. I have never seen any improvement when using the scope after cleaning. Clear Skies Don Colton -----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: Tuesday, April 13, 2004 8:50 AM To: Utah Astronomy Subject: Re: [Utah-astronomy] seeking advice Hi Brent, Maybe I didn't pharse that right. It's an SCT. I don't want to clean the mirror, just the surface of the glass on top, immediately under the lens cap. I thought that was the corrector plate, but maybe I'm wrong! -- 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 _______________________________________________ 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