Tuesday, August 16, 2011

The Ellensburg sky for the week of 8/20/11

Saturday: Sometimes you find a quarter on the ground. Maybe you find a dollar in the lining of your jacket. But how often do you find a galaxy in a well-known part of the sky? The Hubble Space Telescope discovered a face-on spiral galaxy in the Coma Cluster of galaxies about 320 million light years away. This galaxy, called NGC 4911, contains regions of gas and dust as well as glowing newborn star clusters. The Coma Star cluster is in the constellation Coma Berenices, found two and a half fists held upright and at arm’s length above the west horizon at 9 p.m. For more information about this newly discovered galaxy, plus a zoomable image, go to http://hubblesite.org/newscenter/archive/releases/2010/24/.

Sunday: This is a great time to observe Neptune because is in opposition tomorrow night. That doesn't mean Neptune is now a teenager. Opposition means that Neptune is on the opposite side of the Earth as the Sun. An object is in opposition when it is due south 12 hours after the Sun. Thus, when an object is in opposition, it is at its highest point in the sky during the darkest time of the day. Neptune is near the boundary of the constellations Capricornus the sea goat and Aquarius the water bearer, about two and a half fists above the southeast horizon at 11 p.m. It is easy to see with binoculars. First find the bright star Fomalhaut just above the southeast horizon. Neptune is exactly 20 degrees, or two fists held upright and at arm’s length, above Fomalhaut.

Monday: You: “I’d like a chocolate cluster for a snack, please.”
Moon: “Not me. I’d like an open star cluster for breakfast.” The Moon will get its request because it is midway between the Pleiades and Hyades open star clusters this morning in the southeastern sky. These clusters, while not as tasty as chocolate clusters, are regions of the galaxy where very young stars can be found. Stars in the Hyades cluster are about 600 million years old and stars in the Pleiades are a very toddler-like 100 million years old. (By comparison, the Sun is about 5 billion years old.) The Hyades cluster is a little less than a fist below the Moon and the Pleiades is a little less than a fist above the Moon at 5 a.m.

Tuesday: You may have trouble holding in your water at midnight. But not the Big Dipper. The cup of the Big Dipper is facing upward in a water-holding orientation about two fists above the north horizon at midnight.

Wednesday: Vega, the third brightest star visible from Ellensburg and the entire northern section of the United States, flies nearly straight overhead at 9 p.m.

Thursday: Mars is about a half a fist to the upper left of the Moon at 5 a.m.

Friday: The Sun is finally moving out of it period of having few or no sunspots. But while the Sun was inactive, astronomers were studying sunspots on other stars such as Corot-2a, a star that is similar to the Sun but much younger. Astronomers noticed that the brightness drop of Corot-2a was slightly different every time its planet Corot-2b passed in front of it. They thought it should be the same since the same planet was passing in front of it. So, the astronomers concluded the variation in brightness was due to sunspots on Corot-2a. For more information about this, go to http://www.skyandtelescope.com/news/home/49444867.html.

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

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