Wednesday, August 5, 2015
The Ellensburg WA sky for the week of 8/8/15
Saturday: The Perseid meteor shower hits its peak late for the next few nights with Wednesday night and early Thursday morning being the peak of the peak. 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. With dark skies owing to the new or nearly new moon for the whole week, you can see up to 100 meteors per hour in the late night and early morning hours all week. 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: Jupiter and the bright star Regulus are about a pinky-width above the west-northwest horizon at 8:45 p.m. Slightly less challenging is the planet Mercury, two finger widths above the west horizon at this time.
Monday: The bright star Betelgeuse is about one fist to the lower right of the waning crescent moon at 5 a.m.
Tuesday: 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.
Wednesday: Saturn is two fists above the south-southwest horizon at 9 p.m.
Thursday: 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”.
Friday: Many big city dwellers never see the milky white, nearly continuous band of stars known as the Milky Way. As cities grow and add more lights, it has become harder to see the bulk of the Milky Way galaxy, our home in the universe. But, there are two easy ways to see the Milky Way. The first way is to look in the mirror. You are part of the Milky Way. The second way is to look from due north through the point straight overhead (called the zenith) to due south from 10:30 p.m. to 1 a.m. for the next two weeks. This is the time of year when the Milky Way is highest in the sky and away from the city lights on the horizon.
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 http://nightsky.jpl.nasa.gov/planner.cfm.