Full moon

The moon rises Monday evening in Hookset, N.H. (CJ Gunther / European Pressphoto Agency)

Hey there sky watchers, here's a subtle treat for your Monday evening: Tonight you can enjoy the smallest full moon of 2013.

Mini-moon? Sure, you can call it that if you like.

The moon does not move in a perfect circle as it orbits our planet, so there are times in the month when it is closer to us and times when it is farther away. When the moon hits the farthest point from Earth in its elliptical orbit, astronomers say the moon is at apogee. When the moon's orbit takes it closest to us, they say it is at perigee.

When the moon is at perigee, it is about 30,000 miles closer to us than it is when it is at apogee.

"If you can compare a full moon at its very closest to one at its very furthest, you would be able to see a difference," said Tony Cook who heads the telescope program at Griffith Observatory. "But I'm not sure most people are really sensitive to when the moon is closer or when it is further away." 

The moon will turn full at 1:28 a.m. PST tonight (technically early Tuesday morning). The moon will be at apogee Thursday, when it will be 252,432 miles from Earth. So tonight's full moon is not the smallest full moon we could possibly see, but it will be the smallest of 2013.

But next month you will have the opportunity to see an even smaller full moon. The moon will turn full Jan. 15, and it will have been at apogee just a few hours earlier.

Happy sky watching!

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