The Ellensburg, WA sky for the week of July 4, 2020

Saturday: Tonight’s Full Moon is in the constellation Sagittarius. The good news: there

is a penumbral lunar eclipse. The bad news: a penumbral lunar eclipse is where the Moon is in the Earth’s partial shadow and is barely noticeable. But if you want to check “penumbral lunar eclipse” off of your astronomy bingo card, look at the Moon for the 90 minutes after sunset. By 4:00 a.m. tomorrow, the Moon, Jupiter, and Saturn make a two-fist long line going diagonally up from due southwest.

Sunday: Did you see the Moon-Jupiter-Saturn neighborly meeting at 4:00 am this morning? What!? You weren’t up then. That’s okay. They form a small triangle throughout the entire night. They are just above the southeastern horizon at 10:00 p.m., with Saturn to the upper left of the Moon and bright Jupiter to the upper right of the Moon. Follow them throughout the night until they set right after sunrise tomorrow morning.

Monday: Look straight up at midnight. The head of Draco the dragon will be looking straight down on you. The brightest star in the head is called Eltanin. If you wait for a VERY long time, Eltanin will be the brightest star in the entire night sky. Currently 154 light years away, it is moving towards Earth and will be only 28 light years away in about 1.3 million years, claiming the title as the brightest star.

Tuesday: Mars rises a little after midnight. By 1:00 a.m., Mars is a half a fist held upright and at arm’s length above the eastern horizon.

Wednesday: This morning, Venus is at its brightest for this orbital cycle, magnitude -4.5. The magnitude scale is somewhat counterintuitive: the brighter the object appears in the sky, the smaller the magnitude number. Magnitude values are defined so that a magnitude difference of 5 corresponds to a brightness ratio of 100. This morning, Venus is about a thumb width above Aldebaran, a star of magnitude 1.0. Venus appears more than 100 times brighter than Aldebaran because it has a magnitude 5.5 more than Aldebaran. Venus and Aldebaran are a little more than a fist above the eastern horizon at 4:30 a.m.

Thursday: Being in a coma is a bad thing. Looking at the Coma Star Cluster is a good thing. The Coma Star Cluster is an open cluster of about 50 stars that takes up more space in the sky than 10 full Moons. It looks like a fuzzy patch with the naked eye. Binoculars reveal dozens of sparkling stars. A telescope actually diminishes from the spectacle because the cluster is so big and the telescope’s field of view is so small. The Coma Star Cluster is in the faint constellation Coma Berenices (ba-ron-ice’-ez) or Queen Berenice’s hair. Queen Berenice of Egypt cut off her beautiful hair as a sacrifice to the gods for the safe return of her husband Ptolemy III from battle. The Coma Star Cluster is about three fists above the western horizon at 11:00 p.m.

Friday: Mizar is a star in the middle of the Big Dipper handle. Don’t confuse Mizar with its rhyming brother Izar in the constellation Bootes. Izar is also a binary star with about the same apparent brightness. And both were featured in different episodes of Star Trek. Izar was featured in the Star Trek episode “Whom Gods Destroy” from the original series. It is the base of Fleet Captain Garth, a former big shot in the federation and one of Kirk’s heroes before he went insane. Garth kidnaps Kirk and Spock before eventually being outsmarted. Mizar doesn’t play as big a role in its episode. It is the star of the homeworld of one of the alien species in The Next Generation episode “Allegiance”. Izar is one fist above the bright star Arcturus and five and a half fists above the west-southwestern horizon at 11:00 p.m. Mizar is five and a half fists above the northwest horizon at this time.

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.