Thursday, July 23, 2009

The Ellensburg sky for the week of 7/25/09

Saturday: The Southern Delta Aquarid meteor shower peaks for the next few nights and early mornings with the greatest concentration of meteors being visible Tuesday night and Wednesday morning. Meteor showers are named after the constellation from which the meteors appear to originate. These meteors appear to come from a point in Aquarius near the star Delta Aquarii, also known as Skat. This point is about one and a half fists held upright and at arm’s length above the southeast horizon at 1 am tomorrow morning. You can follow this point throughout the night as it will remain a fist above Fomalhaut, the brightest star in that section of the sky. Since the moon sets before 1 a.m. all week, it will not be out to obscure many meteors so you should be able to see close to 15-20 meteors per hour at peak activity. As you Mother might say, dress warm and sit in a comfortable chair for maximum enjoyment. Meteors are tiny rocks that hit the Earth and burn up in the atmosphere.

Sunday: Speaking of meteor showers, the Perseid meteor shower is NASA’s “Go Observe” object for August. The Perseid meteor shower is typically the most easily visible shower of the year for Northern Hemisphere observers. This year, moonlight will interfere with the dimmer meteors during the peak evenings of August 12 and 13. Luckily, Perseid meteors are visible from about the last week in July until the last week in August so you can start watching the Perseid meteor shower this week. The meteors appear to come from a point just below the W of the constellation Cassiopeia. This point is about two fists above the northeast horizon at 11 p.m. tonight. For more information, go to

Monday: Say "Cheese". 158 years ago this month, Vega, in the constellation Lyra the lyre, became the first star ever photographed. The photograph was done at the Harvard Observatory using the daguerreotype process. Vega is the third brightest nighttime star we can see in Ellensburg behind Sirius and Arcturus. Vega is nearly straight overhead at 11:00 tonight.

Tuesday: Tonight’s first quarter Moon is in the constellation Virgo the maiden.

Wednesday: When you think of the Solar System, the main objects that come to mind are the planets and the Sun. But much of the evidence of how the Solar System formed comes from meteors, comets, and asteroids. Scientists have been analyzing the small chunks of rocks and ice that fall to Earth. More recently, astronomers have been studying the rocks and ice in outer space with telescopes and space probes. For example, in July, 2005, the NASA mission Deep Impact smashed into a comet to study its structure. For more information about this rather cold “Hot Topic”, go to

Thursday: Jupiter is one and a half fists above the southeast horizon at 11 p.m.

Friday: Mars is nearly three fists above due east at 4:30 a.m.

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

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