Cold Moon Tonight
Be sure to at least take binoculars out tonight and have a look at the cold and beautiful Moon. Trace its wonderful bright ray systems - such as those that extend from Tycho, Copernicus and Kepler. There is no astronomical target out there able to compete with the details you'll find on the lunar surface!
Tuesday, December 13 - Set the alarm for 4:30 a.m. and bundle up to watch for your one good chance at the Geminid meter shower!
Today in 1920, the first stellar diameter was measured by Francis Pease with an interferometer at Mt. Wilson. His target? Betelgeuse! Tonight let's defy the Moon and have a look at the giant star as we look towards the northeastern corner of Orion.
One of the largest known stars, the Hobbits called it "Borgil" - but in the ancient world the Arabs knew this star as "Beit Alguese." Its bright variability was first noticed by Sir William Herschel in 1836, and followed through its near 6 year cycle of erratic changes. During the phases of expansion and contraction, at smallest Betelgeuse still exceeds the diameter of Earth's orbit around our own Sun. For all of its size, you might think Betelgeuse to be massive - but it's not. Although it exceeds Sol by 160 million times in volume, it has only about 20 times more physical mass!
posted by fusionlin @ 9:53 AM
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