Thursday, August 18, 2016

The Ellensburg WA sky for the week of 8/20/16

Saturday: Jupiter, Venus, and Mercury crowd very low, making a small triangle above due west a half hour after sunset. Jupiter is at the upper left of the triangle, a half a fist held upright and at arm’s length above due west. The bright Venus is less than a fist to the right of Jupiter. Mercury is lost in the glare below Jupiter.

Sunday: Arcturus is two fists above due west at 10:30 p.m. This star, whose name means bear watcher, is the brightest in the sky’s northern hemisphere. It follows Ursa Major, the Great Bear, around the North Star. Arcturus is the closest giant star to Earth. It is one of the few stars whose diameter can be measured directly rather than being inferred from its density and mass, which, themselves are derived from other parameters.

Monday: Had the script been written a little differently for a well-known Robin Williams movie, we might have heard Mr. Williams shout, “Goooood Morning Orion the hunter”. Orion is typically thought of as a winter constellation. But, it makes its first appearance in the summer sky. The lowest corner of Orion’s body, represented by the star Saiph (pronounced “safe”), rises at 3:30 a.m., well before the Sun. By 5:30 a.m., Orion’s belt is nearly three fists above the southeast horizon.

Tuesday: Have you ever gone to a family reunion, looked around and asked, “How in the world are we related to each other?” Astronomers look around the Solar System and wonder if there is life anywhere else that we are related to. The Mars Science Laboratory landed on Mars in 2012 to investigate whether it ever had conditions favorable for life. The Cassini Mission continues to study the plume of complex organic chemicals streaming from Saturn’s moon Enceladus. NASA and the European Space Agency are planning missions to study Europa, the Jovian moon with an ice-covered ocean. And many astronomers consider the methane haze in the atmosphere in Saturn’s moon Titan similar to that of the early Earth. To learn more about the search for life in the Solar System and beyond, go to While you won’t see anyone waving back, you can see Saturn, Mars, and the bright star Antares in a short line segment in the sky. Saturn is two fists above and Mars, which is about twice as bright as the ringed planet, is one and a half fists above the south-southwest horizon. Antares is right below Mars.

Wednesday: Deneb is nearly straight overhead at 11:30 p.m. When you look at Deneb, you are seeing light that left Deneb about 1,800 years ago.

Thursday: In 1987, the rock group Def Leppard sang “Pour some sugar on me, in the name of love. Pour some sugar on me, come on fire me up”. In 2012, some European astronomers “found some sugar near stars, they were very young. Found some sugar near stars, out where planets formed.” Astronomers observed molecules of glycolaldehyde, a simple form of sugar, in the disk of gas and dust orbiting young binary stars. This is the first time astronomers have found this simple sugar so close to a star indicating that organic molecules can be found in planet-forming regions of stars. For more information, go to

Friday: All stars rotate. Our Sun takes a little less than an Earth month to make one rotation. Astronomers have started to study the relationship between mass, stellar rotation, and planetary formation by aiming NASA’s Kepler space telescope toward the Pleiades open star cluster. All 1,000 stars in this group is nearly the same age, 125 million years old. Since all of the stars are the same age and formed from the same set of materials, astronomers have the ideal “laboratory” to isolate the role star mass plays on star rotation and evolution. Read more about the findings at See the Pleiades for yourself, one fist above the east-northeast horizon at 11:30 p.m.

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

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