Wednesday, October 1, 2014
The Ellensburg sky for the week of 10/4/14
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: At 7 p.m., Saturn is one fist above the southwest horizon and Mars is one and a half fists above the south-southwest horizon.
Monday: Along with the not-so-subtle drug reference in their name, The Doobie Brothers made an astronomy reference in their song lyrics: “Old black water, keep on rollin’, Mississippi moon won’t you keep on shining on me.” Astronomers now think that some of the water on Earth may be older than the Solar System. The chemical signature of the water indicates it came from a very cold source, just a few degrees above absolute zero. The early Solar System was much warmer than this meaning the water came from a source outside the Solar System. For more information about the old Earth water, go to http://goo.gl/QsEu5P.
Tuesday: The Draconid meteor shower peaks for the next three nights. The meteors appear to come from a point in the head of Draco, the dragon constellation. This point is about five fists held upright and at arm’s above the northwest horizon at 10 p.m. tonight. This point remains near the trapezoid-shaped head of Draco throughout the night. Typically, this is a minor shower. However, 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 out nearly the entire night so all but the brightest meteors will be obscured. Luckily, tomorrow night brings its own show. For everything you need to know about the Draconid meteor shower, go to http://goo.gl/HGkw0w.
Wednesday: “Red Moon, you saw me sleeping alone. Before the Sun rises up. Before I turn on my phone.” Early risers and late nighters will see a total lunar eclipse this morning. During a total lunar eclipse, the Moon enters the earth’s shadow. Total lunar eclipses are not as obvious as total solar eclipses because light still reaches the Moon even when it is directly behind the Earth. That is because the Earth’s atmosphere acts like a lens and bends rays of light that would normally miss the Moon such that they hit the Moon. That doesn’t mean the Moon looks the same during a total lunar eclipse as it does during a normal full Moon. Sunlight is white. White light is the sum of all of the colors in the visible spectrum (red, orange, yellow, green, blue, indigo and violet). Our atmosphere scatters the blue component of the Sun’s white light. That is why our sky is blue. When the Sun or Moon is near the horizon, the light passes through a lot of the atmosphere meaning a lot of the blue light is scattered and the Sun or Moon looks redder than when it is high in the sky. During a total lunar eclipse, sunlight passes through a large slice of the Earth’s atmosphere. The remaining light that reaches the Moon is reddish. Thus, the Moon looks red during a total lunar eclipse. From our perspective in Washington, the Moon will start to enter the Earth’s shadow at 2:15 a.m. Totality starts at 3:30 a.m. By 4:25 a.m., the total eclipse will be over with the partial eclipse ending about an hour later. For more information about this eclipse, and lunar eclipses in general, go to the Science@NASA video at http://goo.gl/iCnkAu.
Thursday: Jupiter is about four and a half fists above the east-southeast horizon at 6:30 a.m.
Friday: While you are resting after looking for Draconid meteors for two nights, start thinking about the Orionid meteor shower. This shower, which consists of the earth colliding with pieces of the remains of Halley's Comet's tail, peaks on the morning of October 21 but produces meteors from now until early November. These meteors appear to come from a point in Orion, the hunter. This point is about three fists above the southeast horizon at 1 a.m. tonight. You can follow this point throughout the night as it will remain one fist above the prominent reddish star Betelgeuse (pronounced Bet'-el-jews). The Orionid meteors are fast - up to 40 miles per second.
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 https://nightsky.jpl.nasa.gov/planner.cfm.