Friday, August 11, 2017
The Ellensburg WA sky for the week of 8/12/17
Saturday: The Perseid meteor shower hits its peak late tonight/early tomorrow morning. The meteors appear to come from a point just below the W of the constellation Cassiopeia. This point is about two and a half fists held upright and at arm’s length above the northeast horizon at 11 p.m. By dawn, this point is about seven fists above the northeast horizon. If you fall asleep or forget to set your alarm, you will be able to observe this shower from about 11 p.m. to dawn for the next few nights in about the same location in the sky. The Perseid shower is one of the longest lasting showers. The waning gibbous moon will obscure most of the dimmer meteors. For tips about optimizing your viewing this year, go to http://goo.gl/Ylk9jA. As your Mother might say, dress warm and sit in a comfortable chair for maximum enjoyment. These meteors are sand to pea-sized bits of rock that fell off of Comet Swift-Tuttle. They are traveling about 40 miles per second as they collide with the Earth and burn up in the atmosphere.
Sunday: At 9 p.m., Jupiter is one fist above the west-southwest horizon and Saturn is two fists above due south.
Monday: The total solar eclipse is a week from today. If you are lucky enough to find a spot in the path of totality, you know to bring your eclipse glasses. After all, the “total” part of the eclipse lasts two minutes while the partial part lasts two hours. Sky & Telescope magazine has put together a list of things you might not think about needing. Find it at http://www.skyandtelescope.com/2017-total-solar-eclipse/10-things-might-need-eclipse-day/.
Tuesday: Altair, at one corner of the Summer Triangle, is four fists above the southeast horizon at 11 p.m. Altair is one of the closest bright stars, so close that fictional astronauts visited a planet orbiting Altair in the 1956 movie “Forbidden Planet”.
Wednesday: Do you get all of your astronomy news from this column? If so, it is time to up your game. CWU astronomer Cassie Fallscheer is giving a presentation tonight from 6:30 to 7:30 at Hal Holmes Center. Go to https://goo.gl/oEM5vN for more information.
Thursday: Need a caffeine pick-me-up? Make it a double. Need an astronomy pick-me-up? Make it a double double. Find Vega, in the constellation Lyra the lyre, nearly straight overhead at 10:00 tonight. Less than half a fist to the east (or left if you are facing south) of the bright bluish star Vega is the “star” Epsilon Lyra. If you look at Epsilon Lyra through binoculars, it looks like two stars. If you look at Epsilon Lyra through a large enough telescope, you will notice that each star in the pair is itself a pair of stars. Each star in the double is double. Hence, Epsilon Lyra is known as the double double. The stars in each pair orbit a point approximately in the center of each respective pair. The pairs themselves orbit a point between the two pairs.
Friday: Let’s all sing the galactic black hole monster song: “D is for dusty, that’s good enough for me. D is for dusty that’s good enough for me. D is for dusty that’s good enough for me. Oh dusty, dusty, dusty starts with D.” Astronomers know that spiral galaxies such as our own have super massive black holes in the center, black holes that are billions of times the mass of the Sun. They thought they got to be this massive by mergers where two galaxies collide and the gas, dust and black holes at the center of each colliding galaxy form a larger central black hole. But many distant galaxies show no signs of galactic mergers. Astronomers think the black holes at the center of these galaxies grew simply by snacking on the gas and dust that comes from supernova explosions and normal star formation. Just like the Cookie Monster gains weight by snacking on individual cookies rather than eating a cookie factory. Cookie crumbs, I mean dust, block your view of the center of our galaxy. It is about one fist above due south at 10 p.m., between the constellations Sagittarius and Scorpius. For more information, go to http://goo.gl/L9ppJf.
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.