Wednesday, February 17, 2010

The Ellensburg sky for the week of 2/20/10

Saturday: In this, the 200 anniversary of the year of his birth, let’s remember Abraham Lincoln: 16th president, person on the penny, and astronomer. Astronomer? Well, maybe not an astronomer, but someone who used observational evidence from the sky to solve a problem. In 1858, Lincoln defended Duff Armstrong, a family friend who was accused of murder. The prosecution thought they had a strong case because their primary witnesses claimed to have observed the killing by the light of the nearly full moon. Let’s listen in on the trial courtesy of the 1939 film, Young Mr. Lincoln.
Lincoln: How’d you see so well?
Witness: I told you it was Moon bright, Mr. Lincoln.
Lincoln: Moon bright.
Witness: Yes.
(Dramatic pause as Lincoln reaches for something)
Lincoln: Look at this. Go on, look at it. It’s the Farmer’s Almanack. You see what it says about the Moon/ That the Moon… set at 10:21, 40 minutes before the killing took place. So you see it couldn’t have been Moon bright, could it?
Lincoln used the known information about Moon rise and set times for August 29, 1858 as evidence in a trial. You may confirm Lincoln’s findings on the Moon set time by going to, the US Naval Observatory website, and filling out Form A. For more information about Lincoln’s “almanac trial”, go to

Sunday: Tonight’s first quarter moon is in the constellation Taurus. The open star cluster called The Pleiades is about a half a fist held upright and at arm’s length to the right of the Moon at 7 p.m.

Monday: Avast ye matey. Swab the poop deck. Pirates love astronomy. In fact, the term “poop” in poop deck comes from the French word for stern (poupe) which comes for the Latin word Puppis. Puppis is a constellation that represents the raised stern deck of Argo Navis, the ship used by Jason and the Argonauts in Greek mythology. Argo Nevis was an ancient constellation that is now divided between the constellations Puppis, Vela and Carina. The top of Puppis is about a fist and a half to the left of the bright star Sirius in the south-southwest sky at 10 p.m. Zeta Puppis, the hottest, and thus the bluest, naked eye star in the sky at 40,000 degrees Celsius is near the uppermost point in Puppis.

Tuesday: Saturn is about three fists above the southeast horizon at 11 p.m.

Wednesday: Time to do a little word association quiz. I’ll type a word and you say the first thing that comes to mind. Ice. Did you say “cold”? Okay. Sun. Many of you said “bright”. Finally, galaxy. Hum, I bet you said “spiral”. Although there are many types of galaxies, most people’s image of a galaxy is a spiral galaxy. Many astronomers wonder how such stately, orderly-looking collections of stars could have survived the chaotic, collision-filled early universe. Two competing teams of astronomers have developed computer models to try and solve this puzzle. But, you don’t need a computer to enjoy our own spiral, galaxy, the Milky Way. At 7 p.m., the Milky Way rises from the southeast sky, passes straight over head and disappears in the northwest sky.

Thursday: Mars is about a half a fist to the upper left of the Moon at 7 p.m.

Friday: Sirius, the brightest star in the nighttime sky, is two and a half fists above the south horizon at 9 p.m.

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

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