Thursday, October 21, 2010

The Ellensburg sky for the week of 10/23/10

Saturday: “It’s a wonderful day in the neighborhood.” Constellations can be considered neighborhoods in the nighttime sky. But, the stars in those constellations are not necessarily neighbors in real life. For example, the bright stars in the constellation Cassiopeia range from 19 to over 10,000 light years away from Earth. One constellation that consists of real neighbors is Ursa Major. Or, more specifically, the Big Dipper. Five stars in the Big Dipper are all moving in the same direction in space, are about the same age and are all about 80 light years from Earth. “Please won’t you be my neighbor?” Skat, the third brightest star in the constellation Aquarius is a neighbor to these five Big Dipper stars, all of which are about 30 light years from each other. They are thought to have originated in the same nebula about 500 million years ago. Just like human children do, these child stars are slowly moving away from home. Skat is about three fists held upright and at arm’s length above due south at 10 p.m. The much brighter Fomalhaut is a fist and a half below Skat. And, it’s not fun being below Skat.

Sunday: Jupiter is three fists above the southeast horizon at 8 p.m.

Monday: The Stargate movies and TV shows have access to a portal to other planets. Harry Potter has access to a portal to the Chamber of Secrets. You have access to a Portal to the Universe. This portal, available not in Moaning Myrtle’s bathroom but on the web at, is a repository of up-to-date astronomy news, blogs, and podcasts.

Tuesday: Saturn is a little less than a fist above the east horizon at 6:30 a.m.

Wednesday: A few stars appear to be a color other than white to the naked eye. The reddish Betelgeuse in the constellation Orion and the bluish Vega in the constellation Lyra come to mind. But if you look with binoculars, the star Mu Cephei appears to be more vividly colored than either of these - a surprisingly deep red. This star, named the Garnet star by the astronomer William Herschel, is eight fists above the north horizon, very close to being straight overhead, at 8 p.m. It is a red supergiant star that varies in brightness by about a factor of five over a two-year period. If our Sun were replaced by Mu Cephei, it would fill up the solar system out to halfway between Jupiter and Saturn.

Thursday: Pollux is about a fist to the upper left of the Moon at midnight. Castor, the Gemini “twin” of Pollux, is right above it at this time.

Friday: This weekend is Halloween so make sure you loead up on peanut clusters, almond clusters, and open star clusters. That last one will be easy (and cheap, actually free) because two of the most prominent open star clusters in the sky are easily visible in the autumn sky. The sideways V-shaped Hyades Cluster is two fists above due east at 10 p.m. Containing over 300 stars, the Hyades cluster is about 150 light years away and 625 million years old. The Pleiades Cluster, a little more than three fists above due east, is larger at over 1000 stars and younger. Compared to our 5 billion year old Sun, the 100 million year age of the Pleaides is infant-like.

The positional information in this column about stars and planets is typically accurate for the entire week.

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