An alternative to Clear Sky Clock is the excellent "Weather forecast for astronomy" on Environment Canada's site. As well as changing the address, new features have been added to better control the time-lapse cloud and seeing forecasts. http://weatheroffice.ec.gc.ca/astro/index_e.html It is currently very interesting to run animations for the cloud and transparency forecasts, as the onset of the monsoon in Arizona (expected tomorrow) is obvious. IMHO, this is the single most useful product for predicting observing conditions for the next 48 hours. Tom -- See message header for info on list archives or unsubscribing, and please send personal replies to the author, not the list.