Jay: I have found that the weatherman's definition of "clear" doesn't mean that conditions are great for deep sky astronomy. In late spring early summer we have a lot of days listed as clear but the nights are plagued with a high thin cirrus cloud cover. You can see the blue through this and observe the moon and planets, but for galaxies and even star clusters the conditions are really rather poor. Maybe I'm spoiled after being free to observe all I want for the last 10 years, but I find the conditions to be excellent only about 20 nights out of the year. My Idea of a good night is the moon is down for at least half of the night and the temperature doesn't fall below 40F. For social astronomy at Harmons or Wheeler farm, I have a different standard. I just want to be able to show someone the moon, Jupiter or Saturn. These can always burn thru the haze. DT ________________________________ From: Jay Eads <jayleads@gmail.com> To: Utah Astronomy <utah-astronomy@mailman.xmission.com> Sent: Saturday, October 1, 2011 9:37 PM Subject: [Utah-astronomy] Clear, Partly Cloudy and Cloudy Nights This link: http://www.cloudynights.com/ubbthreads/attachments/4837784-Clouds_1.jpg shows a bunch of western cities and the amount of clear days vs partly cloudy and cloudy. Salt Lake is listed as the 45th city with only 34.2% of the total days clear. The break out is 125 clear days, 101 partly cloudy days and a 139 days cloudy. How does that measure with what others may have gathered in terms of data? -- Jay Eads _______________________________________________ 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.slas.us/gallery2/main.php