Christmas Full Moon

Well it won’t be a white Christmas here in Arizona but it will be a bright one, thanks to a full Moon which happens to line up with Christmas day this year.

An interesting fact – the full Moon rises in the east at the same time the Sun sets in the west!  (Local mountains may alter this timing a bit of course.)  This is the result of the Sun, Earth and Moon being in a straight line at the time of full moon.

There are no shadows on the Moon when it is full (think High Noon) but the direct sunlight does make it easy to see a special feature – “rays” of ejecta spreading out from impact craters like the two in the accompanying photo (copyright Steve Mandel, from Astronomy Picture of the Day, August 9, 2001).  Copernicus (upper left) and Tycho (lower right) are fairly recent craters so the blast of ejecta from their formation still overlays the nearby hills and valleys.

The bright ray systems are easy to see in binoculars.  Grab a pair and take a look at this view of the moon that is only visible for a few days each month.

Our next FHAC club meeting will be on Monday, January 11th and our monthly public Star Party will be on Tuesday, January 12th.  Details will be sent out after the holidays.  Stay safe and enjoy the night sky.

Ted

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