Thursday, May 7, 2009

The Ellensburg sky for the week of 5/9/09

Saturday: If the commanding officer in the movie Stripes would ask the Bill Murray character what happens to the star U Scorpii this year, he could reprise his well known quote from the movie and say “Blown up, sir!” U Scorpii is a recurrent nova meaning it explodes at least once a century. Based on records over the past one hundred years, U Scorpii explodes about once every ten years. Its last eruption was in 1999. You do the math. When U Scorpii explodes, it gets over 2,000 times brighter in only five hours going from a star visible in large telescopes to a star visible in binoculars. U Scorpii, if it was visible, would be to the upper left of the Moon at midnight tonight.

Sunday: Jupiter is two fists held upright and at arm’s length above the southeast horizon at 5 a.m.

Monday: Give me an “M”. Give me a “3”. What does that spell? “M3.” “Big deal,” you say. It was a big deal to French comet hunter Charles Messier (pronounced messy a). M3 was the 3rd comet look-alike that Messier catalogued in the late 1700s. M3 is a globular cluster, a cluster of over 100,000 stars that is 32,000 light years away. It is too dim to be seen with the naked eye but is fairly easy find with binoculars. First find Arcturus five and a half fists above the southeast horizon at 10 p.m. (See Wednesday’s entry to learn how to find Arcturus.) Move your binoculars up a little so two stars of nearly identical brightness are in your field of view. When the top star is in the lower left part of your field of view, there should be a fuzzy patch near the center of your field of view. This is M3.

Tuesday: Venus is one fist above the east horizon at 5 a.m. Mars is about one fist to the loser left of Venus.

Wednesday: This is a good time of the year to find the Big Dipper. It is nearly straight overhead at 10 p.m. The cup is to the west and the handle is to the east. You can always use the Big Dipper to find some other bright stars. First, follow the curve, or arc, of the Big Dipper down three fists into the southern sky. This is the bright star, Arcturus, the second brightest nighttime star we can see in Ellensburg. Next, continue on a straight line, or spike, another three fists down toward the south horizon to the star Spica. Spica is the tenth brightest nighttime star we can see in Ellensburg. You now know how to use the Big Dipper handle to “arc” to Arcturus and “spike” to Spica.

Thursday: The latest fad on hard rock is groups are covering 1980s songs. Disturbed covers “Land of Confusion” by Genesis. Seether covers “Careless Whisper” by Wham. How about covering a song by The Police? An appropriate one this week is “King of Pain”: “There’s a little black spot on Saturn today. You would not have seen it yesterday.” The shadow of Titan, Saturn’s largest moon, passes across Saturn from 10:26 tonight until 3:39 tomorrow morning. This should be visible in high quality small telescope, one with a light gathering lens or mirror at least three inches in diameter. Saturn is four and a half fists above the southwest horizon at 10:26 p.m.

Friday: Wait a minute. We got all the way to the end of the week with no Moon phase summary? How can that be? There are 29.5 days between the same Moon phase in two different cycles. That means about 7.5 days between the phases new, first quarter, full and last quarter. Since a week is seven days, there are some weeks in which none of the main phases occur. This week, the Moon was always in the waning gibbous phase.

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

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