Thursday, September 29, 2016

The Ellensburg WA sky for the week of 10/1/16

Saturday: Since Halloween is later this month; the stores are filled with bags of candy clusters. Instead, take time to look at a star cluster. The Hyades cluster is an open star cluster that represents the V-shaped face of Taurus the bull. It is one of the biggest and nearest star clusters with about 200 stars 150 light years away. The Hyades cluster was the first cluster to be the subject of detailed motion studies. These studies allowed astronomers to pinpoint the distance to the Hyades and provide important information about the scale of the universe. Aldebaran, nearly two fists held upright and at arm’s length above the east horizon at 11 p.m., is a foreground star and not a part of the Hyades cluster.

Sunday: Mercury is a half a fist above due east at 6 a.m.

Monday: Mnemonics are helpful for remembering astronomy facts. (Similarly, “Johnny Mnemonic”, the 1995 cyberpunk film, was helpful in getting Keanu Reeves’ career going.) After all, school children all around the country are learning the order of the planets by remembering, “My very excellent mother just served us nine….” Oops, I guess that one needs updating. Well, here’s one that will not need updating for nearly 100,000 years: the order of the stars in the Big Dipper. Because the nighttime stars are so far away from us, their actual motion through the sky, called their “proper motion” is not noticeable over even thousands of years. That is why the constellations have remained the same since ancient times. But two stars in the Big Dipper have a proper motion large enough such than in 100,000 years, the stars will no longer make a dipper shape. Until then, you can remember the names of the seven dipper stars in order from handle to cup by remembering this helpful advice for teens: “AM, ask mom. PM, dad”. The stars are Alkaid, Mizar, Alioth, Megrez, Phad, Merek, and Duhbe. The Big Dipper is one fist held upright and at arm’s length above the north horizon at 11 p.m.

Tuesday: At 7 p.m., Venus is a half a fist above the southwest horizon. It’s the brightest object in that part of the sky. Saturn is two fists to the upper left of Venus, nearly one and a half fists above the southwest horizon. Finally, Mars is one and a half fists above the south-southwest horizon.

Wednesday: Winter is coming to the morning sky. The “winter constellations” such as Orion, Taurus, and Gemini are high above the southern horizon at 6 a.m. They are called winter constellations because they are high in the sky during the evening viewing hours of the winter months.

Thursday: The last two columns described liquid methane on Saturn’s moon Titan and a possible liquid water ocean beneath the surface of Saturn’s moon Enceladus. But the most exciting water proclamation came last week when astronomers announced the presence of 125-mile long plumes of water shooting up from cracks in the ice on Jupiter’s moon Europa. It’s been long thought that Europa has an ocean under many kilometers of ice and that this ocean is one of the most promising places in the Solar System to harbour life. Instead of sending a lander to drill through the think ice, astronomers can send a much easier to design probe to catch and analyze the water from space. For more information about Europa’s water plumes, watch the video at

Friday: The Draconid meteor shower peaks tonight and tomorrow night. The meteors appear to come from a point in the head of Draco, the dragon constellation. This point is nearly straight overhead at 7 p.m. tonight. This point remains near the trapezoid-shaped head of Draco throughout the night. Unlike most meteor showers, this one is best observed in the early evening rather than after midnight. Call this the “early to bed” meteor shower. Draconid meteors are slow moving which means you will have a easy time differentiating true Draconid meteors, from Comet 21P/Giacobini-Zinner, from stray grains of dust that happen to enter the Earth’s atmosphere near where we see the constellation Draco. The moon will be in the waxing crescent phase, near the south-southwest horizon, at peak viewing time so this might be your lucky meteor watching time. For everything you need to know about the Draconid meteor shower, go to

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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