You really don't want to get into the statistics of observing weather. I = did it last year after looking at Brian Skiff's historical photometric = evening data. It was sobering, and more than a bit depressing. So, in the spirit = of the recent weather posts, here goes: All numbers are rounded up. If I remember correctly, something less than 120 nights per year are = truly clear. Call that a 33% or 1/3 probability. Now, if you can only go out = on weekends, that gives a ~29% or 2/7 nights available in any week. Now = factor in new moon weekends . . . let's be generous and say every month has two observing weekends (a stretch). So that's 50% or 1/2 the available = weekends. So we have .33 x .29 x .5 =3D .047, a little less than 5% That's for the whole year, so .047 x 365 =3D ~17 nights on average of photometric nights falling on a "new moon" weekend per year, or 8 = weekends. If you factor in whether the clear nights are consecutive (all factors = in this excerise are constrictive), the odds would take another hit, albeit = a small one. But I won't go there. This is enough of a bummer. 17 nights would be OK if everyone always went out for both nights, but = that is not possible for most people. So, divide by two again and we have ~8 nights. And of course I can't/won't factor in life/family/job etc . . . <insert happy face emoticon here> In 2004 I made it out about five times. Due to my personal = circumstances, this year I probably won't be out at all until the fall (hopefully). So what's a star-hugger to do? Seek councilling, dream of pristine = nights past, make telescopes (of course) and maybe buy a Planetarium: http://antiqueradio.org/art/spitz01.jpg <name withheld> Tom uttered: =20 -----Original Message----- From: az-observing-bounce@xxxxxxxxxxxxx [mailto:az-observing-bounce@xxxxxxxxxxxxx] On Behalf Of Tom Polakis Sent: Tuesday, February 15, 2005 12:18 PM To: AZ-Observing@xxxxxxxxxxxxx Subject: [AZ-Observing] Percent of Possible Sunshine In addition to not seeing a lot of starlight this Autumn/Winter, it = seemed like we're also not seeing a lot of sunlight. Here is a table of the = last few months of data for percent of possible sunshine from the Phoenix NWS office, with a comparison to the averages and lows since 1896. The = daytime cloudiness has been bad, but not extremely so. Percent of Possible Sunshine Oct Nov Dec Jan Feb (so far) 2004-5 88 75 72 64 53 1896-1995 Avg 88 84 78 78 80 =20 Low 65 62 47 54 47 Current weather and recent climate data is available at: http://www.wrh.noaa.gov/Phoenix/ ...and "The Climate of Phoenix" archived data is at: http://geography.asu.edu/cerveny/phxwx.htm I will resist saying that we are on track to set a new record low for February sunshine, as that would be like saying that the Suns are on = track to win 70 games when they were midway through the season. Tom -- See message header for info on list archives or unsubscribing, and = please=20 send personal replies to the author, not the list. -- See message header for info on list archives or unsubscribing, and please send personal replies to the author, not the list.