Wednesday, July 9, 2014

The Ellensburg sky for the week of 7/12/14

Saturday: Today’s full moon isn’t a normal full moon. It’s a supermoon. Since the moon’s orbit around the Earth is elliptical, it is not always the same distance away from the Earth. When it is closer to the Earth, the moon looks larger than when it is farther away. One popular definition of a supermoon is a new or full which occurs when the moon is at or near its closest approach to the Earth for a given orbit. Also a supermoon has an alter ego that people don’t recognize despite being the same size, having the same voice, and never being in the same place at the same time as its super hero version. Read more about the supermoon and the radioactive spider that bit it at

Sunday: Would you like to take the small finger test? First, find Mars and Spica at 10 p.m., two fists held upright and at arm’s length above the southwest horizon. Mars is the redder and brighter of the two. If you can fit your finger between Mars and Spica, you pass the test. They’ll be moving apart over the next few nights so keep taking the test until you pass.

Monday: Mercury is near Venus in the morning sky for the next few days. Look for Mercury to move toward Venus until Wednesday morning when they’ll be about a half a fist apart, low in the east-northeast sky at 4:30 a.m.

Tuesday: Being in a coma is a bad thing. Looking at the Coma Star Cluster is a good thing. The Coma Star Cluster is an open cluster of about 50 stars that takes up more space in the sky than 10 full Moons. It looks like a fuzzy patch with the naked eye. Binoculars reveal dozens of sparkling stars. A telescope actually diminishes from the spectacle because the cluster is so big and the telescope’s field of view is so small. The Coma Star Cluster is in the faint constellation Coma Berenices (ba-ron-ice’-ez) or Queen Berenice’s hair. Queen Berenice of Egypt cut off her beautiful hair as a sacrifice to the gods for the safe return of her husband Ptolemy III from battle. The Coma Star Cluster is about three fists above the west horizon at 11:00 p.m.

Wednesday: The long summer days remind us to take some time to safely observe the Sun. The best way to do that is to go to and watch the great images and videos that come from the Solar Dynamics Observer, or SDO for short. We are just moving away from a sunspot maximum so the Sun has been very active lately. So what, you say? Sunspots and associated phenomena greatly influence the strength of solar flares. The strongest flares can affect satellites orbiting the Earth and even electronics on the Earth’s surface.

Thursday: Say "Cheese". 164 years ago today, Vega, in the constellation Lyra the lyre, became the first star ever photographed. The photograph was done at the Harvard Observatory using the daguerreotype process. Vega is the third brightest nighttime star we can see in Ellensburg, behind Sirius and Arcturus. Vega is nearly straight overhead at 11:00 tonight.

Friday: Saturn is about two and a half fists above the south-southwest horizon at 10 p.m.

The positional information in this column about stars and planets is typically accurate for the entire week. For up to date information about the night sky, go to

No comments: