Wednesday, December 24, 2008

The Ellensburg sky for the week of 12/27/08

Saturday: 2009 has been proclaimed the International Year of Astronomy (IYA) by scientific organizations all over the world. Why 2009? It is the 400th anniversary of Galileo first using a telescope to study the sky and of the publication of Astronomia Nova, Kepler’s ground breaking book about the motion of the planets. You can find information about IYA activities at My favorite IYA website is, NASA’s effort to educate us about all aspects of astronomy. Each month, NASA has picked a “Hot Topic” and something to “Go Observe!”. January’s hot topic is telescopes and space probes. The planet Venus leads off the year as the first object to observe. Venus holds a special place in the history of astronomy as being the first object, other than the Moon, to be observed to go through phases. The specific pattern of phases, first observed by Galileo, provides evidence that the Earth is not at the center of the Solar System. Stay tuned to this space about IYA events in Ellensburg.

Sunday: Saturn is one fist held upright and at arm’s length above due east at 11:30 p.m. What does it mean to be “one fist held upright and at arm’s length above due east?” Make a fist with your right hand. Hold it out in front of you at arm’s length. Do you feel like you can “fight the power”? Good. Now, hold your fist vertical so your thumb is on top. The angular distance from the top of your fist to the bottom is 10 degrees. Place the top part of your fist at eye level. This represents zero degrees. Now, stack the left fist on top. The top of this fist is 10 degrees above the horizon. Any celestial object even with the top of your left fist is about 10 degrees above the horizon. If you were to hold your left fist steady and move your right fist on top of the left, the top of the right fist would be about 20 degrees above the horizon.

Monday: Jupiter is about a half a fist above the southwest horizon at 5:15 p.m. Mercury is about a finger’s width to the lower left of Jupiter.

Tuesday: Antares is about a half a fist above the southeast horizon at 7 a.m.

Wednesday: Forget about that big bright ball in Times Square. You can mark the start of the new year with one of the sky’s own big bright balls. That perennial favorite New Year’s Day marker, Sirius, the brightest star in the night sky, rises to its highest point in the sky a little after midnight on January 1. Thus, when Sirius starts to “fall”, the new year has begun. Look for Sirius about two and a half fists above due south at midnight.

Thursday: Today is the day we celebrate something new – a new classification of celestial objects. Giuseppe Piazzi discovered Ceres [pronounced sear’-ease], the first of what are now called “asteroids”, on January 1, 1801. Ceres is the largest asteroid in the belt between Mars and Jupiter. At first, Piazzi thought it was a star that didn’t show up on his charts. But, he noted its position changed with respect to the background stars from night to night. This indicated to him that it had to be orbiting the Sun. August 2006, Ceres got promoted to the status of “dwarf planet” by the International Astronomical Union.

Friday: Tonight’s weather forecast: showers. Meteor showers, that is. The Quadrantid meteor shower peaks tomorrow morning making tonight and tomorrow the best night to see meteors. Meteor showers are named after the constellation from which the meteors appear to originate. That makes this shower mysterious because there isn’t any constellation with this name now. The shower was named after Quadrans Muralis, an obsolete constellation found in some early 19th century star atlases. These meteors appear to come from a point in Draco the dragon. This point is about three fists above the northeast horizon at 1 a.m. In good years, careful observers can spot about 100 meteors per hour. This could be a good year because the waxing crescent moon sets at 11:30 p.m. meaning the prime viewing time will be moon free. Meteors are tiny rocks that hit the Earth and burn up in the atmosphere. Most meteors are associated with the path of a comet. This shower consists of the debris from an asteroid discovered in 2003.

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

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