Thursday, December 6, 2018
The Ellensburg WA sky for the week of 12/8/18
Saturday: Warrant, the American glam metal band (as labeled by Wikipedia) was singing about carbon stars in its 1991 hit “I Saw Red”. The lyrics for the astronomy version are “Then I saw red, when I looked up in the sky, I saw red, Orion’s bright star it was by.” R Leporis, also known as Hind’s Crimson Star, is one of the reddest stars in the sky. It is a star near the end of its life that has burned its helium nuclei into carbon. Convective currents, like those in a pot of boiling water, bring this carbon to the surface. There it forms a layer of soot that scatters away the light from the blue end of the visible spectrum leaving the light from the red end of the spectrum to reach our eyes. For more information about Hind’s Crimson Star and a list of other deep red stars, go to http://goo.gl/EnhRe4. Hind’s Crimson star is one fist to the lower right of Rigel, the brightest star in Orion. You’ll need binoculars or a small telescope to see it Hind’s Crimson star. But you can easily spot Rigel two fists held upright and at arm’s length above the southeast horizon at 9 p.m.
Sunday: If you had a difficult time seeing red on last night, here is an easier red target. Mars is three and a half fista above due south at 6 p.m.
Monday: It’s getting too cold to see frogs in the wild. Some rich politicians see them on their dinner plate. But this is a great time to see frogs in the sky. Ancient Arabs referred to the stars that we now call Fomalhaut and Diphda as Ad-difdi al-awwal and Ad-difda at-tani. This means the first frog and the second frog, respectively. Both frogs are low in the southern sky at 5:41 p.m. Fomalhaut is nearly one and a half fists above due. The slightly dimmer Diphda is two fists above the south-southeast horizon.
Tuesday: The bright star Capella is nearly straight overhead at midnight.
Wednesday: The Geminid meteor shower peaks early the next two mornings. Meteor showers are named after the constellation from which the meteors appear to originate. These meteors appear to come from a point in Gemini the twins. This point is about six fists above the southeast horizon at midnight tonight. You can follow this point throughout the night, as it will remain near the bright star Castor, the right hand star of the “twin” stars Pollux and Castor. By 4 am, it is four fists above the southwest horizon. This shower is typically one of the best ones of the year producing bright, medium speed meteors with up to 120 meteors per hour under ideal conditions near the peak. This year IS near ideal because the Moon is near the first quarter phase so it sets before the peak time.
Most meteor showers occur when the Earth passes through the orbital trail of a comet. The broken off comet fragments collide with the Earth and burn up in the atmosphere. Astronomers had searched for a comet source for this shower since 1862 when the shower was first observed. Finally, in 1983, astronomers discovered the object that created the fragments that cause the meteor shower. To their surprise, it was a dark, rock that looked like an asteroid, not a shiny icy comet. Astronomers named this object Asteroid 3200 Phaethon. For more information about the Geminid shower, go to https://goo.gl/f4qMqg.
Thursday: Columbia the dove, representing the bird Noah sent out to look for dry land as the floodwaters receded, is perched just above the ridge south of Ellensburg. Its brightest star Phact is about one fist above the south horizon at midnight.
Friday: This morning is Mercury’s greatest western elongation. So what, you say? Not so what. This means Mercury is far from the Sun in the sky. So what, you say? Not so what. This means that Mercury is easy to observe. It is one fist above the southeast horizon at 7 am. To the lower left of Mercury is Jupiter, about three times brighter but more in the glare of the Sun. To the upper right of Mercury is the much brighter Venus, two and a half fists above 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 https://nightsky.jpl.nasa.gov/planner.cfm.