The Ellensburg WA sky for the week of 12/5/15

Saturday: The earliest sunset of the year occurs throughout the next week: 4:13 p.m. This seems odd because the shortest day of the year, the winter solstice, isn’t for about two more weeks. The Sun is at its southernmost point with respect to the background stars on the day of the winter solstice. This means the Sun spends the least amount of time above the horizon on that day. But, the sunrise and sunset times depend on more than its apparent southward motion in the sky. It also depends on where the Sun is on the analemma, that skinny figure-8 you see on globes and world maps. During the second week in December, the Sun is not quite to the bottom of the analemma. But, it is on the leading edge of the analemma, the first section to go below the horizon. For a slightly different explanation about this, go to http://goo.gl/kjnHP. Or just go watch the sunset. But don’t stare at the Sun.

Sunday: The Oort cloud object called Comet Catalina has made its way into the morning sky for northern observers. Early estimations called for it to be visible with the naked eye comet but recent measurements rate it as a 6th magnitude object. This makes binoculars a necessity. For this morning and the next few mornings, look for Comet Catalina about a half a fist to the left of Venus. First find Venus, the brightest point of light in the sky, two fists held upright and at arm’s length above the southeast horizon. Aim your binoculars so Venus is in the right hand portion of your binocular field of view. Comet Catalina will be on the left hand side of the field of view. For more information about viewing Comet Catalina, go to http://goo.gl/9b4F23.

Monday: Yesterday I suggested you use binoculars to find Comet Catalina. You may have scoffed, thinking only the purity of the naked eye or the glory of a telescope are the ideal routes to astronomy enjoyment. Oh no. Binoculars are a great tool observing the sky. They are small, relatively inexpensive, and easy to use. After looking for Comet Catalina this morning, move your binoculars westward to look at the Moon. You’ll see a few craters on the lit side and a few long shadows along the light-dark border called the terminator. For more information about using binoculars, go to http://goo.gl/xWwYkb.

Tuesday: Do you look into a nursery and say, “it’s a boy” or “it’s a girl”? Not me. I say, “It’s a star”. Of course, I like looking into a stellar nursery – a star-forming region such as the Orion Nebula in the middle of Orion’s sword holder. The Orion Nebula looks like a fuzzy patch to the naked eye. Binoculars reveal a nebula, or region of gas and dust, that is 30 light years across. The center of the nebula contains four hot “baby” stars called the Trapezium. These hot stars emit the ultraviolet radiation that causes the Nebula’s gas to glow. The Orion Nebula is three fists above the southeast horizon at 11 p.m.

Wednesday: 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 three fists above the southeast horizon at 10 p.m.

Thursday: You can see red again this morning, the red planet. Mars is three fists above the southeast horizon at 6 a.m. Jupiter and its Great Red Spot is four and a half fists above the south horizon at this time.

Friday: Fomalhaut, the southernmost bright star visible from Ellensburg, is a little less than one and a half fists above due south at precisely 5:38 p.m. Set your watch by it. (“Mommy, what is a watch?”)

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.