Wednesday, August 10, 2016
The Ellensburg WA sky for the week of 8/13/16
--> Saturday: Sometimes you find a quarter on the ground. Maybe you find a dollar in the lining of your jacket. But how often do you find a galaxy in a well-known part of the sky? The Hubble Space Telescope discovered a face-on spiral galaxy in the Coma Cluster of galaxies about 320 million light years away. This galaxy, called NGC 4911, contains regions of gas and dust as well as glowing newborn star clusters. The Coma Star cluster is in the constellation Coma Berenices, found two and a half fists held upright and at arm’s length above the west-northwest horizon at 10 p.m. For more information about this recently discovered galaxy, plus a zoomable image, go to http://goo.gl/5OXUX.
Sunday: Saturn, Mars, and Antares make an equilateral triangle about a fist and a half above the south-southwest horizon at 9 p.m. Mars, the brightest of the three objects, is on the right hand side and Saturn is on the top.
Monday: 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.
Tuesday: Hit the road Mercury. And don’t you come back no more, no more. For a few weeks, Mercury has been hitting the road and moving away from the Sun in the sky. Today, Mercury is as far away from the Sun as it will get on the evening half of this cycle. This is known as its greatest eastern elongation. Yet, this distance does not translate into good viewing because Mercury will be very low in the sky…. Wait a minute. Look back at the April 16, 2016 entry of this column. I wrote the exact same thing. Am I just lazy, taking advantage of the secret organizations paying me a million doll hairs to write this column? Yes, I am. But, the statement is true once again and will be true in a few months. As the closest planet to the Sun, Mercury moves back and forth from the morning to the evening sky several times a year. In addition, it never gets very far from the Sun in the sky so it is almost always difficult to view.
Tonight, Mercury is less than a half a fist above due west at 8:30 p.m., between the much brighter Jupiter to its left and Venus to its right. Over the next few weeks, Mercury will move toward the Sun in the sky. After it passes in front of the Sun, it will appear in the morning sky by the end of September.
Wednesday: 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.
Thursday: The August full moon was called the full sturgeon moon by Midwest and northeastern Native American tribes because the sturgeon in lakes in this part of the country were easiest to catch during this full moon time.
Friday: Hercules stands six fists above the southwest horizon at 10:00 this evening. Four moderately bright stars form a lopsided square that represents his body, while his head points southward.
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.