All Clear Sky Charts – “Created by the late Attilla Danko and maintained by CSCCharts, it’s the astronomers forecast. It shows at a glance when, in the next 96 hours, we might expect clear and dark skies for one specific observing site. There are many, but the example above is for Winer Observatory (the most sponsored chart). It’s is specifically intended for amateur astronomers. The data comes a forecast model developed by Allan Rahill of the Canadian Meteorological Center. Read from left to right. Locate a column of blue blocks. That’s when the sky will likely to be clear and dark. A more detailed explanation is here, but the short version is: the clear sky chart predicts hourly cloud cover, atmospheric transparency and seeing. (Good “seeing” occurs when the air is steady enough to allow you to see fine detail on planets through a telescope.) That means you can plan whether to observe galaxies or planets or stay home and process image data. If you find this image, or the underlying forecast maps, useful please email Allan Rahill. He needs to show his bosses at CMC that his astronomy forecasts are actually being used. Feel free to copy me. If you find the charts very useful and want more frequent updates and more features use the chart pages more.”