Tonight's full Moon is a "Blue Moon." It's the second full Moon this month and the first Blue Moon to fall on New Year's Eve in nearly 20 years. Sounds like a rare excuse for a party... There's more. In Europe, Africa and Asia, the Blue Moon will dip into Earth's shadow for a partial lunar eclipse. At maximum eclipse, around 19:24 Universal Time, approximately 8% of the Moon will be darkly. Blue Moons are rare (once every 2.5 years). Blue Moons on New Year's Eve are rarer still (once every 19 years).