The Ellensburg, WA sky for the week of May 30, 2020

An alien was in control of my brain last week when I said there would be a Virtual Planetarium Show this week. It is next Saturday.

Saturday:  Cygnus the swan flies tonight. Deneb, the brightest star in the constellation, whose name means “tail” in Arabic, is about two fists held upright and at arm's length above the northeastern horizon 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, which is 25 light years away. Vega is three and a half fists above the east-northeastern horizon at this time.

Sunday: The questions who, what, where, and when can only be asked with a “W”. At 9:30 p.m., the W-shaped constellation Cassiopeia is about one and a half fists above due north. The middle star in the W was used as a navigation reference point during the early space missions. The American astronaut Gus Grissom nicknamed the star Navi, his middle name Ivan spelled backwards. After he died in the Apollo 1 fire, the star name was kept as a memorial.

Monday: 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 start on a different day each year. This year, the month would have started about a week and a half ago on the day of the last New Moon. Tonight the Moon is in the waxing gibbous phase, nearly four fists above due south at 10:00 p.m. The bright star Spica is less than a fist below the Moon. Juno’s husband, Jupiter, rises at about midnight. By 12:30 a.m., it is about a half a fist above the southeast horizon.

Tuesday: The bright star Arcturis is six fists above due south at 10:30 p.m. Cor Caroli is the medium bright star about three fists to the upper right of Arcturus, halfway between Arcturus and the Big Dipper Cup. About halfway between Arcturus and Cor Caroli is M3, an eight billion year old globular cluster of 500,000 stars. You’ll need binoculars to find it. It looks like an out-of-focus star right next to an in-focus star just below it. For more information about M3, go to https://skyandtelescope.org/astronomy-news/hello-messier-3/.

Wednesday: Two years ago, NASA picked the Jezero Crater as the landing site of the Mars 2020 Rover, called Perseverance. The edge of the crater contains a dried river delta that flowed into the crater on and off over a period of hundreds of thousands of years. If the sediments from the dry periods were buried quickly, any organic materials would have been buried with the sediments. These would be the clues of life that Perseverance will be looking for.  For more information about Jezero Crater, visit https://tinyurl.com/ybuwp4qx. Mars is about two fists above due southeast at 4:30 a.m.

Thursday: As the weather warms up, people start thinking about swimming in a nice cool body of water. Recently, astronomers have 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. While you need a very large telescope to see Enceladus, Saturn is less than a half a fist above the southeast horizon at 12:30 a.m., just to the left of the much brighter Jupiter. They are both two fists above due south at 4:30 a.m.

Friday: The CWU campus is closed. But astronomy learning lives on! The Physics Department and the College of the Sciences is hosting a First Saturday VIRTUAL planetarium show tomorrow from noon to 1:00 p.m. CWU professor Bruce Palmquist will host the Intergalactic Planetarium Short “Film” Festival. You’ll see a variety of short Worldwide Telescope Tours created by CWU Astronomy and Douglas Honors College students featuring videos about the Solar System, star formation, and Harry Potter astronomy. Stay at home, practice good physical distancing, and visit https://cwu.zoom.us/meeting/register/tJcuduChqz8jGdQ86cUyKBKmR2K_jdcEqSx- to register for the Virtual tour.

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.