Thursday, July 16, 2009

The Ellensburg sky for the week of 7/18/09

Saturday: 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 four fists held upright and at arm’s length above the west horizon at 10:30 p.m.

Sunday: Mars, Venus and the Moon make an obtuse triangle low in the eastern sky early this morning. Venus, the brightest planet, is at the obtuse angle, a half a fist to the right of the Moon. Mars is about a fist to the upper right of Venus. At 4:30 a.m., the triangle is two fists above the east horizon.

Monday: Take a two and a half hour walk. Too long, you say? Forty years ago today, Neil Armstrong and Buzz Aldrin took the first ever walk by humans on another world. They spend two and a half hours setting up scientific instruments and collecting rocks for study back on Earth. Michael Collins orbited the Moon in the spacecraft the three astronauts would use to return to Earth. There is a special news conference featuring NASA astronauts from 6:30-7:30 a.m. Pacific Daylight Time to commemorate the event. At 9:30 a.m. Pacific Daylight Time, NASA astronauts and officials will answer questions from people at science museums all across the country. Both of these events will be broadcast live today on NASA-TV and at For more information about 40th anniversary events, go to

Tuesday: Just as we did for the previous new Moon, it is time to revisit that well known astronomy version of the Blondie hit song The Tide is High. In the astronomy version, Debbie Harry sang: “The tide is high ‘cause the moon is new. Higher still when the moon’s close, too.” The last two new Moons have occurred near when the Moon is at perigee. Tides are high during the new Moon phase because the moon and Sun are both stretching the Earth in the same direction causing the ocean water in line with the Sun and moon to be pulled upward. Tonight's moon is new. When the Moon is at perigee, it is at its closest to the Earth which accentuates the upward pull on the water and makes the tides really high.

Wednesday: Jupiter is one fist above the southeast horizon at 11 p.m.

Thursday: Do you wish it was easy to find due north? After all, a compass points to magnetic north which is a few degrees off of true geographic north. Well, tonight’s your night. Capella, the brightest star in the constellation Auriga the Charioteer, is due north at exactly 10:14 p.m. It looks like a bright light on a pole on the north ridge because is only about one degree above the horizon.

Friday: Saturn is one fist above the west horizon at 9:30 p.m.

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

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