The Ellensburg, WA sky for the week of May 25, 2024

Saturday: Cygnus the swan flies tonight. Deneb, the brightest star in the constellation, whose name means “tail” in Arabic, is two and a half fists held upright and at arm’s length above due northeast at 10:00 p.m. Cygnus’ wings make a vertical line one half a fist to the right of Deneb. Its head, marked by the star Albireo, is two fists to the right of Deneb. While Deneb is at the tail of Cygnus, it is at the head of the line of bright stars. It is 160,000 times more luminous than the Sun making it one of the brightest stars in the galaxy. It does not dominate our night sky because it is 2,600 light years away, one of the farthest naked eye stars. If Deneb were 25 light years away, it would shine as bright as a crescent moon. Compare that to Vega, its fellow Summer Triangle star. Vega IS 25 light years away and certainly doesn’t rival the light of the crescent Moon. Vega is about two fists to the upper right of Deneb.

Sunday: Spica is less than a half a fist to the lower left of the moon. Both are more than three fists above due south at 10:30 p.m.

Monday: Stonehenge was created on the island of Great Britain by Neolithic people. “Manhattanhenge” was created on the island of Manhattan by modern day architects and construction workers. Twice a year, the end of May and mid-July, the setting Sun aligns perfectly with the Manhattan grid pattern. That means observers will see the Sun set at the end of the street. The first Manhattanhenge sunset is tonight at 8:13 p.m. Eastern time and then again tomorrow at 8:12 p.m. Eastern time. For more information about Manhattanhenge, go to https://www.amnh.org/research/hayden-planetarium/manhattanhenge.

Tuesday: For the next few weeks, you are going to have to get up early to observe any naked eye planets. Mars is less than a fist above due east at 4:30 a.m.

Wednesday: The bright red giant Antares is about one and a half fists above the south-southeastern horizon at 11:30 p.m.

Thursday: Altair, the lowest star in the Summer Triangle, is one fist above due east at 10:45 p.m.

Friday: As the weather warms up, people start thinking about swimming in a nice cool body of water. A few years ago, astronomers discovered evidence of an ocean about 20 miles beneath the surface of Saturn’s moon Enceladus. NASA’s Cassini probes measured variations in how the moon’s gravity pulled on the orbiting spacecraft. These variations can be explained by a large amount of liquid water under one section of the ice because liquid water is denser than an equal volume of ice. More recently, scientists have discovered organic molecules in the geyser streaming out of cracks in the surface. Now they hypothesize that the organic molecules come from hydrothermal vents, like those found under Earth’s oceans, and are working on discovering the creation mechanism. For more information about these, go to https://www.universetoday.com/166987/linking-organic-molecules-to-hydrothermal-vents-on-enceladus/. While you need a very large telescope to see Enceladus, you can see Saturn to the upper right of the moon at 4:30 a.m., one and a half fists above due southeast.

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.