Thursday, June 24, 2010

The Ellensburg sky for the week of 6/26/10

Saturday: Don’t wait until the 4th of July to go to those wimpy firecracker shows. Find the hypergiant star Rho Cassiopeiae. Astronomers think that Rho Cassiopeiae will likely go supernova (explode) in the near future. Of course, for stars, near future might mean today. It might mean 20,000 years from now. Rho Cassiopeiae is in the constellation Cassiopeia the queen. At 11:00 tonight, Cassiopeia looks like the letter “W” about three fists held upright and at arm’s length above the northeast horizon. Rho Cassiopeiae is about a finger’s width to the right of the rightmost star in the “W”. Once you find it you’ll be thinking, “Big deal, I can hardly see it.” Although it is barely visible to the naked eye, it is actually very bright. It is the 20th most luminous star in the sky, a whopping 550,000 times more luminous than the Sun.

Sunday: Ah, the continuing dilemma for any king, even a little one: love or war. Regulus, the 20th brightest star in the night sky, Latin for “little king”, is midway between the planets Mars, named for the god of war, and Venus, named for the god of love. At 10 p.m., Regulus is one and a half fists above due west. Mars is about a fist to its upper left and Venus is about a fist to its lower right. Of the two, I pick love. It is much brighter.

Monday: Saturn is two fists above the west-southwest horizon at 10:30 p.m. If you look through a small telescope at this time, you’ll be able to see its two largest moons, Titan and Rhea, off to its side. Titan is the 10th largest and Rhea is the 20th largest object in the solar system. For more information on identifying Saturn’s moons in a small telescope, go to

Tuesday: Two of the dogs in the sky have set: Canis Major and Canis Minor. Both are represented by stars that are very close and very bright. Sirius, in the constellation Canis Major, is the brightest nighttime star and the 8th closest. Procyon, in the constellation Canis Minor, is the 7th brightest nighttime star and the 20th closest. But, canines are still represented in the sky by Canes Vanatici, the hunting dogs. They are four fists above the west-northwest horizon at midnight, underneath the Big Dipper handle.

Wednesday: The constellation Cepheus the king (husband of Cassiopeia the queen) is about four fists above the northeast horizon at 11 pm. Cepheus is about one and a half fists above Cassiopeia. Cepheus looks like a house on its side with the roof peak pointing towards the west. Cassiopeia and Cepheus revolve around the North Star every night like a happy couple going through life together.

Thursday: When people find out that you read this column, they may ask you all sorts of tough astronomy questions such as “Where can I see the Milky Way?” That one is easy. Just look in the mirror. We are all part of the Milky Way. The center of the Milky Way galaxy is in the direction of the constellation Sagittarius, about one and a half fists above due south at 11:30 p.m. The Milky Way is NASA’s “Go Observe” object for July. For more information, go to

Friday: You won’t be able to see Jupiter unless you either stay up late or get up early. Jupiter is about a half a fist above the east horizon at 1 a.m. By 4 a.m., it is three fists above the southeast horizon.

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

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