Summer officially comes to end tonight at 10:09pm. If clouds stay away, you might notice some unusual brightness tonight. That’s because the harvest moon arrives tonight. It’s unusual for this annual full moon phase to come as summer comes to an end. The moon will reach maximum brightness just a few hours after the passing of summer, producing an unusually bright night across the U.S.
NASA’s Dr. Tony Phillips wrote a great article explaining the phenomena. He says usually, the Harvest Moon arrives a few days to weeks before or after the beginning of fall. It’s close, but not a perfect match. The Harvest Moon of 2010, however, reaches maximum illumination a mere six hours after the equinox. This has led some astronomers to call it the "Harvestest Moon" or a "Super Harvest Moon." There hasn’t been a comparable coincidence since Sept 23, 1991, when the difference was about 10 hours, and it won’t happen again until the year 2029.