Thursday, January 22, 2009

The Ellensburg sky for the week of 1/24/09

Saturday: Draco Malfoy makes an appearance in all seven books of the Harry Potter series. Perhaps you’ve heard of these. But, the constellation Draco the dragon makes an appearance in the sky every night. It is a circumpolar constellation as viewed from Ellensburg meaning it never goes below the horizon. The head of the dragon is one fist held upright and at arm’s length above due north at 9 p.m. Eltanin, the brightest star in the constellation, is at one corner of the trapezoid-shaped head of Draco.

Sunday: Saturn is about one fist above the east horizon at 10 p.m. For more information about Saturn, go to http://solarsystem.nasa.gov/planets/profile.cfm?Object=Saturn.

Monday: If you are planning a trip to the Indian Ocean or Indonesia today, you will see an annular solar eclipse. Despite the word similarity, annular does not mean once a year. Annular means “ring-shaped”. An annular solar eclipse occurs when the Moon, as seen from Earth, is relatively far from Earth in its orbit and not large enough to cover the Sun even though they are nearly perfectly lined up. Three days ago, the Moon was at apogee, or the farthest point from the Earth in its orbit. By today, its apparent size still is not big enough to cover the entire Sun. Instead, there is bright ring or annulus around the Moon. The resulting eclipse is called an annular solar eclipse because of this ring.
Here is the difference between a total solar eclipse and an annular solar eclipse. Take a coin out of your pocket. Close one eye. Hold the coin close to your open eye such that you completely cover a round object across the room. This represents a total eclipse of that object. Now, slowly move the coin away from your eye until you can see an outline of the round object. This is an annular eclipse of that object. Your coin, representing the Moon, has too small of an angular size to completely cover the round object across the room, representing the Sun.

Tuesday: The bright star Arcturus is about a half a fist above the east-northeast horizon at 11 p.m.

Wednesday: “The crow rises at midnight” said spy number one. “It arrived in the southeast sky” replied spy number two. “I’m sorry. I don’t recognize that code” added spy number three. Spy one exclaimed, “That’s because it’s not a code, you idiot. I’m talking about the constellation Corvus the crow.” This is very bad spy movie dialogue to remind you that Corvus had a very bad life. According to one myth, Corvus brought the god Apollo the news that his girlfriend was seeing someone else. In a classic case of punishing the messenger, Apollo turned the crow black. The box-shaped Corvus is rising above the southeast horizon at midnight tonight, just like the spies said.

Thursday: Venus is less than a half a fist to the upper left of the Moon this evening. They are about one foot above the west horizon at 8 p.m. For more information about Venus, go to http://solarsystem.nasa.gov/planets/profile.cfm?Object=Venus.

Friday: Spica, the brightest star in Virgo, is a half a fist above the east-southeast horizon at 6 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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