Friday, August 10, 2018
The Ellensburg WA sky for the week of 8/11/18
Saturday: The Perseid meteor shower hits its peak Sunday and Monday mornings. 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 Moon will be new or close to new for the next few nights. For tips about optimizing your viewing this year, go to http://earthsky.org/?p=2087. 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: Mars is one and a half fists above due south at 11:45 p.m.
Monday: Saturn is two fists above due south at 10 p.m.
Tuesday: Need a caffeine pick-me-up? Make it a double. Need an astronomy pick-me-up? Make it a 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 . 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 Cluster, commonly known as the Coat Hanger cluster because of its resemblance to an coat hanger. The cluster is six fists above the south 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: Seventeenth century astronomers documented the appearance of a new star, or “nova”, in 1670. However as modern astronomers studied the records of the star, called Nova 1670, they realized it didn’t have the characteristics of a typical nova because it didn’t repeatedly brighten and dim. It brightened twice and disappeared for good. Turning their telescopes to the region, they discovered the chemical signature to be characteristic of a very rare collision of two stars. For more information about this discovery, go to http://goo.gl/rJnC2G. Nova 1670 is right below the binary star system , the head of Cygnus the swan. is seven fists above the south horizon at 11 p.m.
Jupiter is a little more than a half a fist to the lower left of the Moon. They are low in the southwestern sky at 9 p.m.
Friday: This evening, Venus is as far away from the Sun in the sky as it will get this orbital cycle. What is this "farthest away" point known as? It is known as the planet’s greatest eastern elongation. is one of the best nights of the year to observe Venus because it is far from the Sun at sunset. Venus is one fist above the west-southwest horizon at 10 p.m. Over the next two months, Venus will move toward the Sun in the sky and get closer to the horizon. By the end of September, it will be lost in the glare of evening twilight.
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.