At Bryce Canyon NP in June I had an interesting conversation with John Dobson regarding the gegenschein. I've always understood that the source of both the zodiacal light and gegenschein is sunlight reflected from interplanetary comet dust. In his characteristic way, John said, "NO!" According to John, the source is actually reflected sunlight from dust-size fused silica (glass) beads blasted from the surface of the Moon by impacts. Recently, I read a similar explanation at some website that I cannot now locate. Has anyone else heard this theory and know how well accepted it is? Does anyone know of other sources for the theory? (Not that I don't trust John Dobson, of course.) Also, for either theory, does anyone know at what distance the dust/glass is supposed to be from Earth that reflects the sunlight? Kim -----Original Message----- From: utah-astronomy-bounces@mailman.xmission.com [mailto:utah-astronomy-bounces@mailman.xmission.com] On Behalf Of Kurt Fisher Sent: Wednesday, September 05, 2007 12:41 PM To: utah-astronomy@mailman.xmission.com Subject: [Utah-astronomy] Bryce Canyon trip - Look for gegenschien please For those of you going to Bryce, I would appreciate it you would look gegnschien at the following predicted opportunities computed for Salt Lake City. Bryce times, az and alts should be similar: Date MDT Az Alt 09/07/2007 01:00:00 171 42 09/08/2007 01:00:00 171 43 09/09/2007 01:00:00 171 43 09/10/2007 01:00:00 171 44 09/11/2007 01:00:00 171 44 For those of you who have not seen it, here are some photos: http://www.swisseduc.ch/stromboli/volcano/photoastro/gegenschein-en.html?id= 11 http://www.swisseduc.ch/stromboli/volcano/photoastro/gegenschein-en.html http://antwrp.gsfc.nasa.gov/apod/ap061226.html - Kurt P.S. - This may post twice; my email server does not appear to be working right. Earlier in the year, I posted a gegenschien sighting opportunity calendar. http://members.csolutions.net/fisherka/astronote/astromath/2007GegenschienEp hemerisSLC.html _______________________________________________ Sent via CSolutions - http://www.csolutions.net _______________________________________________ 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 ______________________________________________________________________ This e-mail has been scanned by Cut.Net Managed Email Content Service, using Skeptic(tm) technology powered by MessageLabs. For more information on Cut.Nets Content Service, visit http://www.cut.net ______________________________________________________________________ Internal Virus Database is out-of-date. Checked by AVG Free Edition. Version: 7.5.484 / Virus Database: 269.12.1/963 - Release Date: 8/20/2007 5:44 PM Internal Virus Database is out-of-date. Checked by AVG Free Edition. Version: 7.5.484 / Virus Database: 269.12.1/963 - Release Date: 8/20/2007 5:44 PM