The Ellensburg, WA sky for the week of August 17, 2019

Saturday: “The sky is black (or light polluted), the stars are white (or red or orange or yellow or blue), the whole world gazes upon the sight (except where there are too many city lights or people are lazy.” Wow. It is difficult to write a flowing set of lyrics when there are so many parenthetical thoughts. Most people think of the sky’s blackness as a lack of stars. But dark patches in the Milky Way are actually massive clouds of dust that are blocking the stars behind them. Two of the most prominent are dark nebulae B142 and B143 in the constellation Aquila the eagle. These are easy to find and enjoy with binoculars. First find the bright white star Altair, five fists held upright and at arm’s length above the southeastern horizon at 10 p.m. Then move your binoculars up a little bit to the next bright star Tarazed, about one fifth as bright. B142 and B143 are to the upper right of Tarazed. They make an “E” shape in the sky; fitting because it was American astronomer E. E. Barnard who first proposed that these were dust clouds and not simply big spaces between the stars. For more information about dark nebula, including many more to look at with binoculars, go to https://goo.gl/9tiqdh. 

Sunday: Jupiter is one and a half fists above the south-southwestern horizon and Saturn is two fists above the southern horizon at 10:00 p.m.

Monday: Fomalhaut, the southernmost bright star, is a half a fist above the southeastern horizon at 11:30 p.m.

Tuesday: 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.

Wednesday: If you want to show your loved ones a celestial sign that they should hang up their clothes, show them Brocchi's Cluster, commonly known as the Coat Hanger cluster because of its resemblance to an upside down coat hanger. The cluster is six fists above the southern horizon at 11 p.m., midway between Altair and Vega, the two brightest stars in the Summer Triangle. You'll need binoculars to make out the shape. First find Altair five fists above the south horizon. Slowly move your binoculars up toward Vega. You will run into the coat hanger along the way. And while you are at it, put away your shoes.

Thursday: 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 the southern horizon at 10 p.m., between the constellations Sagittarius and Scorpius. For more information, go to http://goo.gl/L9ppJf.

Friday: The Moon is in the Hyades Cluster late tonight at 2:00 a.m. The bright star Aldebaran is about a thumb width to the lower right of the Moon. 

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.