Thursday, August 4, 2011

The Ellensburg sky for the week of 8/13/11

Saturday: When the Moon is full, it is difficult to see dim objects in the sky because of the sky glow. But why struggle to find dim objects when there is so much to see on the big, bright object in front of you? The lunar crater called Tycho is best seen during a full Moon. Tycho was formed about 109 million years ago when an asteroid struck the Moon, leaving a crater over 50 miles in diameter and ejected dust trails that radiate out hundreds of miles in all directions. For more lunar highlights, go to, a resource of the Night Sky Network.

Sunday: Many big city dwellers never see the milky white, nearly continuous band of stars known as the Milky Way. As cities grow and add more lights, it has become harder to see the bulk of the Milky Way galaxy, our home in the universe. But, there are two easy ways to see the Milky Way. The first way is to look in the mirror. You are part of the Milky Way. The second way is to look from due north through the point straight overhead (called the zenith) to due south from 10:30 p.m. to 1 a.m. for the next two weeks. This is the time of year when the Milky Way is highest in the sky and away from the city lights on the horizon.

Monday: Need a caffeine pick-me-up? Make it a double. Need an astronomy pick-me-up? Make it a double-double. Find Vega, in the constellation Lyra the lyre, nearly straight overhead at 11:00 tonight. Less than half a fist to the east (or left if you are facing south) of the bright bluish star Vega is the “star” Epsilon Lyra. If you look at Epsilon Lyra through binoculars, it looks like two stars. If you look at Epsilon Lyra through a large enough telescope, you will notice that each star in the pair is itself a pair of stars. Each star in the double is double. Hence, Epsilon Lyra is known as the double-double. The stars in each pair orbit a point approximately in the center of each respective pair. The pairs themselves orbit a point between the two pairs.

Tuesday: You think the Ellensburg wind is bad. Some of the Jovian planets have winds of over 1000 miles per hour. Jupiter and Saturn have belts of clouds that can be observed with back yard telescopes. You’ll have to look quickly to see Saturn. It is a half a fist held upright and at arm’s length above the west horizon at 9:30 p.m. In a few days, it will be lost in the glare of the Sun. To learn more about Saturn and other windy worlds, go to

Wednesday: Deneb is about seven fists above the east horizon at 10 p.m. When you look at Deneb, you are seeing light that left Deneb about 1,800 years ago.

Thursday: Fomalhaut, the bright star in the Piscis Austrinus, the Southern Fishes, is about one fist above the southeast horizon at midnight. It is the southernmost bright star visible from Ellensburg.

Friday: Jupiter, another windy planet, is a half a fist to the lower right of the Moon at midnight tonight. The Great Red Spot on Jupiter is a storm larger than the Earth that has been raging for over 400 years.

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

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