Thursday, April 16, 2009

The Ellensburg sky for the week of 4/18/09

Saturday: This week is National Dark Sky Week, a time during which people in the United States are encouraged to turn off any unnecessary outdoor lights in order to temporarily reduce light pollution. Light pollution is the adverse effect of unwanted light including sky glow, glare, and light clutter. If you think that there is not much sky glow, or wasted light, in the world, look at the nighttime image of the Earth at http://www.cc.gatech.edu/~pesti/night/. While turning off a few unnecessary outdoor lights for one week will not solve the problem of light pollution, National Dark Sky Week will raise awareness of the issue. You can do your own dark sky test. At 10 p.m., look in the sky starting at the southwest horizon, moving to about halfway up in the western sky and back down to due north. If you can see the faint glow of the Milky Way Galaxy, you are observing from a dark site.

Sunday: At 5:30 a.m., Jupiter is less than a finger’s width to the lower left of the Moon. They are low in the southeast sky.

Monday: The Lyrid meteor shower peaks over the next two nights. The meteors appear to come from a point to the right of the bright bluish star Vega in the constellation Lyra the lyre. This point is about three fists above the east-northeast horizon at midnight tonight and close to straight over head near dawn. The best time to look is just before dawn since that is when the radiant, or point from which the meteors appear to come, is high in the sky. For most of the night, the Moon will be below the horizon meaning the sky will be dark enough to see dim meteors. This shower produces about 15 meteors, tiny rocks that hit the Earth and burn up in the atmosphere, every hour during the peak. The Lyrid meteor shower has historical interest because it was one of the first ones observed. Chinese records say “stars fell like rain” in the shower of 687 B.C.

Tuesday: Saturn is exactly five fists above due east at 10 p.m.

Wednesday: Who can forget that well known astronomy tune, “I saw Venus kiss a crescent Moon, low up in the eastern sky so bright.” At 5 a.m., Venus will just to the left of the crescent Moon. At 5:25, the Moon will pass between the Earth and Venus leading to a Venus occultation. At 6:25, about 20 minutes after sunrise, Venus will reappear from behind the right side of the Moon right at the Three o’clock position on the Moon. Since the right hand side of the Moon is not illuminated and about the same color as the rest of the sky, it will look like Venus appeared out of thin air. If that’s too early, go outside a 10 a.m. The thin crescent Moon and Venus will be four and a half fists above the south-southeast horizon. Look at the Moon through a pair of binoculars. Venus will be to the right of the Moon. Then, move your binoculars from your eyes while looking at the Moon and Venus. You should still be able to see Venus about a finger’s width to the right of the Moon even though it is daytime. For an extra challenge, try to find Mars. It is about a half a fist below the Moon.

Thursday: At 5:30 a.m., Venus is about a fist and Mars is about a half a fist above the east horizon.

Friday: You read a lot in this column about Sirius, the brightest star in the nighttime sky and the main star in Canis Major, the Greater Dog. But, you don’t read as much about Canis Minor, the Lesser Dog, and its brightest star, Procyon. Procyon is the seventh brightest star in the nighttime sky and the fifth brightest visible from Ellensburg. Procyon is four fists above the southwest horizon at 9 p.m. I guess Procyon and Canis Minor just need a better public relations team.

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

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