Thursday, October 16, 2008

The Ellensburg sky for the week of 10/18/08

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: Don’t look up at 10 p.m. tonight. There is a lizard overhead. You looked up, didn’t you? Lacerta the lizard is a small constellation located between the much more prominent constellations Cassiopeia and Cygnus. It is straight overhead at 10 p.m. tonight.

Monday: The Orionid meteor shower consists of the earth colliding with pieces of the remains of Halley's Comet's tail. This shower peaks this tonight into early tomorrow morning. This is not a meteor shower that results in a meteor storm. There will be about 15-20 meteors per hour, many more meteors than are visible on a typical night. The chance of seeing meteors this year is less than usual because the last quarter moon will be in the sky during the peak viewing times. Meteor showers are named after the constellation from which the meteors appear to originate. These meteors appear to come from a point in Orion, the hunter. This point is about three fists above the southeast horizon at 1 a.m. tonight. You can follow this point throughout the night as it will remain one fist above the prominent reddish star Betelgeuse (pronounced Bet'-el-jews). The Orionid meteors are fast - up to 40 miles per second. If you fall asleep tonight, you can catch the tail end of the shower every night until early November.

Tuesday: Buzzz. Tonight’s last quarter moon is in the constellation Cancer near the near Beehive Cluster.

Wednesday: Hit the road Mercury. And don’t you come back no more, no more. For a few weeks, Mercury has been hitting the road and moving away from the Sun in the sky. This morning, Mercury is as far away from the Sun as it will get this cycle. This is known as its greatest western elongation. Mercury is about a half a fist above the east horizon at 6:30 a.m. Over the next few weeks, Mercury will move toward the Sun in the sky.

Thursday: Jupiter is one fist above the southwest horizon at 9 p.m.

Friday: Saturn is two and a half fists above the east-southeast horizon at 6:30 a.m.

The positional information in this column about stars and any planet except Mercury is accurate for the entire week.

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