Thursday, May 29, 2014
The Ellensburg sky for the week of 5/31/14
Saturday: The bright star Antares is about a fist held upright and at arm’s length above the south-southeast horizon at 11 p.m.
Sunday: The month of June is named after Juno, the queen of the Roman gods and the mythological protector of the Roman state. In ancient Rome, the month began when the crescent moon was first seen in the evening sky from Capitoline Hill in Rome. If we still started months this way, June would have started a couple of days ago, right after the moon was last new. Celebrate the first sunset in June by actually watching it… and then keeping your gaze fixed on the west-northwest horizon until it is dark enough to see Mercury, Jupiter, and the moon in a line pointing away from the Sun. At 9:30 p.m., Mercury is about a half a fist above the west-northwest horizon, Jupiter is two fists above the west horizon, and the moon is… well, if you have found Jupiter, the can find the moon.
Monday: In 1979, the group Foreigner recorded the song “Head Games”. They could have been singing about the constellations Hercules and Ophiuchus when they said “head games, it’s just you and me baby, head games, I can’t take it anymore” because the heads of these two constellations have been right next to each other in the nighttime sky for all of human history. And just to make it easy for you, a star that bears an Arabic name that means “the head” represents each head. In Hercules, it's Ras Algethi (head of the kneeler); in Ophiuchus, Ras Alhague (head of the serpent charmer). At 11 p.m., Ras Alhague, the brighter of the two, is a little more than four fists held upright and at arm’s length above the southeast horizon. Ras Algethi is about a half a fist to the upper right of Ras Alhague.
Tuesday: Nearly 400 years ago, Galileo viewed the Pleiades star cluster through his telescope and saw that the seven or so stars in the region visible to the naked eye became many more. There are two main types of star clusters. Open star clusters are groups of a few dozen to a few thousand stars that formed from the same cloud of gas and dust within our galaxy. Stars in open star clusters are young as far as stars go. Globular clusters are groups of up to a few million stars that orbit the core of spiral galaxies such as our own Milky Way. One of the most well known star clusters is the globular cluster in Hercules, an object that is fairly easy to find with binoculars. First find Vega, the bright bluish star five fists above the east horizon at 11 p.m. Two fists above Vega is a keystone shape. Aim your binoculars at the upper left hand star of the keystone. The globular cluster is one third of the way to the rightmost star of the keystone. It looks like a fuzzy patch on the obtuse angle of a small obtuse triangle. If you don’t know what an obtuse angle is, you should not have told your teacher, “I’ll never need to know this stuff”.
Wednesday: Mars is three fists above the southeast horizon at 11 p.m.
Thursday: You can set your watch tonight by carefully observing Segin, the left-most star in the W-shaped Cassiopeia. It will be due north at exactly 10 p.m. However, another star in Cassiopeia is causing astronomers to doubt whether or not they can use neutron stars as the most precise known clocks in the universe. Neutron stars have such a precise spin rate that they are used to set clocks on Earth. But the neutron star called 1E 2259+586 (how’s that for a celebrity baby name) exhibited a spin glitch that astronomers had never seen before. To find out more about this new excuse for being late, go to http://goo.gl/C4V8R1.
Friday: Saturn is three fists above due south at 11 p.m.
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.