Tuesday, March 29, 2016

The Ellensburg WA sky for the week of 4/2/16

Saturday: Some people in town today for the Yakima River Canyon Marathon may be looking for a little running inspiration. While nothing can take the place of a 20+ mile long run for marathon preparation (I know), certain objects in the night sky are inspiring. In the Bible, Job specifically mentions the star Arcturus, or the bear keeper, to his friend as a sign of God's majesty. He describes God as that "Which maketh Arcturus, Orion, and Pleiades, and the chambers (constellations) of the south" (Job 9:9, King James Version). Whatever your religious beliefs, it is clear that Job was impressed with this very bright star. See the star that inspired Job about two and a half fists held upright and at arm’s length above the east horizon at 10 p.m.

Sunday: If you ran far yesterday, you don’t want to stay up late looking at the stars. So do something during the day that will help you and other night sky enthusiasts: make sure your outdoor light fixtures are shielded or at least facing down. This will cut down on light pollution, stray light that obscures the stars, and give you a head start in celebrating International Dark Sky week, which starts tomorrow. Go to http://goo.gl/w6Hi7 for more information on how to do an outdoor lighting audit and get more information about International Dark Sky week. You won’t need to have dark skies to see Jupiter four fists above due southwest at 9 p.m.

Monday: It you didn’t run the Yakima River Canyon Marathon two days ago, satisfy that marathon craving by attending a virtual Messier Marathon. Charles Messier (pronounced messy a) was an 18th century French astronomer best known for his catalog of 110 nebulae and star clusters. Amateur astronomers love to find as many of these as they can in one night. During the online Messier Marathon, you’ll see the images broadcast on the Internet. The fun starts this morning at 11:00 a.m. Pacific Daylight Time (when astronomers on the nighttime side of Earth point their telescopes towards interesting celestial objects). For more information, go to http://goo.gl/e2cYkS.

Tuesday: The bright star Sirius is one and a half fists above the southwest horizon at 10 p.m.

Wednesday: Can’t sleep? Catch Saturn and Mars just above the southeast horizon at 1 a.m. Mars is the pale red dot a little more than a half a fist above the southeast horizon. Saturn is about half as bright and a half a fist to the lower left of Mars.

Thursday: The elusive Mercury is a half a fist above the west-northwest horizon at 8:30 p.m.

Friday: Two weeks ago, I asked you to watch the bright star Deneb to observe how its time at due north changes from night to night. It reached due north at 9:27 p.m. two Fridays ago. Tonight, it reaches due north at 8:32 p.m., 55 minutes earlier. As the Earth revolves around the Sun, it also rotates on its axis. (Wow Bruce, really? We learn so much from you!) Because it does both motions counterclockwise as viewed from above the Earth’s North Pole, any given spot on Earth faces the distant stars a little bit earlier each day than that spot faces the Sun. Based on the specific rotational and revolution speed, it amounts to three minutes and 56 seconds earlier each day. That’s 27.5 minutes earlier each week and… wait for it… wait for it… 55 minutes earlier every two weeks. Depending on where you live, those due north times may be off by a few minutes. But the two-week difference will be the same no matter where you live. (I apologize for my smart aleck statement earlier. You DO teach us a lot.)

The positional information in this column about stars and planets is typically accurate for the entire week. For up to date information about the night sky, go to http://nightsky.jpl.nasa.gov/planner.cfm.

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