The Ellensburg, WA sky for the week of October 12, 2024

 Saturday: Comet Tsuchinshan-ATLAS moved into the evening last week. It will be visible in the evening west-southwestern sky for the next two weeks. At 7:00 p.m., the comet will be about a half a fist above the western horizon. That will be difficult to see in the bright twilight sky. By the end of the week, it will be higher in the sky but dimmer. There is a map of where to find the comet right after sunset for the next two weeks at https://skyandtelescope.org/astronomy-news/get-ready-for-comet-tsuchinshan-atlas-the-best-is-yet-to-come/. The sky locations on the map are for 0 hours Universal time on the dates listed. That is about sunset Pacific Daylight Time the day before. So, the symbol labeled 14 corresponds to the sky location for about sunset on October 13.

Sunday: Jupiter is over one and a half fists above the eastern horizon at 11:00 p.m. That means that Jupiter’s moons can be seen tonight, as well. In 2022, NASA’s Juno spacecraft sent back some of the most detailed images of Jupiter’s icy moon Europa. For more about the images and the rest of Juno’s mission, go to https://www.jpl.nasa.gov/news/nasas-juno-gets-highest-resolution-close-up-of-jupiters-moon-europa. With a small telescope, you will be able to see all four of Jupiter’s largest moons at this time. Callisto, the most distant from Jupiter, is on one side of Jupiter, with Callisto being the farthest of all the moons. Europa and Io are on the other side, with Io being the closest of all the moons.

Monday: Saturn is less than a fist to the right of the moon throughout the night. They are three and a half fists above the southern horizon at 10:30 p.m.

Tuesday: Rho Cassiopeiae is the most distant star that can be seen with the naked eye by most people. It is about 8,200 light years away. That means that the light that reaches your eyes from that star left over 8,000 years ago, before the beginning of time according to the Byzantine calendar. Rho Cassiopeiae is six fists above the northeastern horizon at 8:00 p.m., just above the zigzag line that marks the constellation Cassiopeia.

Wednesday: You’ve seen all the top 100 lists: top 100 ways to bench press, top 100 Uzbek astronomers, etc. Now get excited for this week’s full Moon by reading about and finding some of the lunar 100. Go to http://goo.gl/ldGvH6. This list describes 100 interesting landmarks on the Moon that are visible from Earth. They are listed from easiest to see, starting with the entire moon itself at number 1, to most difficult (Mare Marginis swirls, anyone?). Stay up all night to binge watch the moon or just make a few observations a month. It’s your decision. It’s our moon. Start your viewing tonight at 7:00 p.m. when the Moon is one fist above due east. I suggest starting with Mare Crisium, the circular, dark, basaltic plain in the upper right-hand portion of the moon. Items such as Crisium were named "Mare" by early astronomers who mistook them for seas, instead of the hardened lava beds that they really are.

Thursday: The constellation Vulpecula, the fox, stands six fists above due southwest at 9 p.m. It is in the middle of the Summer Triangle, which is defined by the bright stars Vega, Deneb, and Altair. The fox is so faint that you need dark skies to see it.

Friday: Along with the not-so-subtle drug reference in their name, The Doobie Brothers could have made an astronomy reference in their song lyrics if they would have written: “Old Earth water, keep on rollin,’ Mississippi moon won’t you keep on shining on me.” Astronomers now think that some of the water on Earth may be older than the Solar System. The chemical signature of the water indicates it came from a very cold source, just a few degrees above absolute zero. The early Solar System was much warmer than this meaning the water came from a source outside the Solar System. For more information about the old Earth water, go to https://www.skyatnightmagazine.com/news/earth-water-formed-billions-years-ago-before-sun.

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. All times are Pacific Time unless noted.