The Ellensburg WA sky for the week of 5/12/18

Saturday:  You know Metis and Thebe and Adrastea and Amalthea. Io and Ganymede and Callisto and Europa. But do you recall? There are 69 Jovian moons in all.  Just 60 years ago, Jupiter was thought to have only 12 moons. But, astronomers are red-nosed with delight that the advent of supersensitive electronic cameras has caused the number of discovered moons to rapidly increase. Jupiter’s 69 moons range in size from Ganymede, with a diameter of 5,262 kilometers, to S/2002 J12 and S/2003 J9, with a diameter of only one kilometer. Our moon has a diameter of 3,475 kilometers. (One kilometer is 0.62 miles.) Saturn is second place in the moon race with 62. Uranus is next with 27. Then comes Neptune with 14, Mars with 2, and Earth with 1. Even dwarf planets have moons. Pluto has 5, Eris has 1, Haumea has 2, and Makemake has 1. Eris is an outer solar system object that was discovered in 2005 and named in September of 2006. Because astronomers thought it was larger than Pluto, people called it the tenth planet for a while. (More recent measurements show Eris to be a little smaller than Pluto.) Haumea, the newest dwarf planet with a moon, was discovered in 2004 and officially named a dwarf planet on September 17, 2008. Go to http://goo.gl/Xkoeq for more information about Solar System moons. 

Sunday: So you think your mother has problems on Mother’s Day because she had you as you as a child? Her mother issues can’t be as bad as Cassiopeia’s issues. First, she was chained to a chair for boasting about her beauty. Second, she has to revolve around the North Star night after night. Third, her daughter Andromeda was nearly killed by a sea monster. Look for poor Cassiopeia about one and a half fists held upright and at arm’s length above the north horizon at 10 p.m. Cassiopeia looks like a stretched out “W”. 

Monday: Are you up at 2:51 a.m., looking due north and thinking you see a UFO coming to take you away? That's no UFO. It's the bright star Capella, a circumpolar star that never goes below the horizon as viewed from Ellensburg.  

Tuesday: Jupiter is two and a half fists above the south-southeast horizon at 11 a.m. 

Wednesday: Give me an “M”. Give me a “3”. What does that spell? “M3.” “Big deal,” you say. It was a big deal to French comet hunter Charles Messier (pronounced Messy A). M3 was the 3rd comet look-alike that Messier catalogued in the late 1700s. M3 is a globular cluster, a cluster of over 100,000 stars that is 32,000 light years away. It is too dim to be seen with the naked eye but is fairly easy find with binoculars. First find Arcturus six fists above the southeast horizon at 11 p.m. Move your binoculars up one binocular field of view so two stars of nearly identical brightness are in your field of view. When the top star is in the lower left part of your field of view, there should be a fuzzy patch near the center of your field of view. This is M3.  

Thursday: Venus is less than a fist to the left of the young crescent Moon at 10 p.m. 

Friday: Mars’ two small moons, Phobos and Deimos, are not visible in typical backyard telescopes. But they are an interesting study. The prevailing view among most astronomers is that they are captured asteroids. That makes sense given Mars’ proximity to the asteroid belt. But resent findings by European astronomers indicate that Phobos is very porous and made of material similar to the surface of Mars. This implies that Phobos may consist of chunks of Martian debris that was blasted off by numerous impacts and gravitationally bound together. Unfortunately, the Russian Phobos-Grunt probe launched late 2011 to collect material from Phobos crashed to Earth after malfunctioning. For more information about this recent model of Phobos’ formation, go to http://goo.gl/8sw3rM. For more information about Mars, look due south early in the morning. Mars and Saturn are both two fists above the horizon and on either side of due south at 5 a.m. Mars is a little bit east (to the left) of due south and Saturn is a little bit to the west (to the right) of due south. 

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.  

The Ellensburg WA sky for the week of 5/5/18

Saturday: The CWU Physics Department and the College of the Sciences is hosting its first Saturday planetarium show today from noon to 1 pm. CWU physics professor Tony Smith will honor mothers with a presentation about mothers in the night sky. It's certainly not a man's world up there! There will be a show at noon on the first Saturday of every month hosted by different CWU astronomers and astronomy educators. These shows are free and open to all ages. The planetarium is room 101 in Science Phase II, just off the corner of 11th and Wildcat Way, H-11 on the campus map found at https://www.cwu.edu/facility/campus-map. 

Sunday: Mother’s Day is a week away. What are you going to get her? Get her a Gem(ma). The star Gemma, also known as Alphekka, is the brightest star in the constellation Corona Borealis, the Northern Crown. Gemma, Latin for jewel is the central gemstone for the crown. It is four fists held upright and at arm’s length above due east at 10 p.m. 

Monday: Venus is one and a half fists above the west-northwest horizon at 9 p.m. 

Tuesday: Ah, the signs of spring. Trees budding. Flowers blooming. Young lovers frolicking. The Spring Triangle rising. In order of brightness, Arcturus, Spica, and Regulus form a triangle that rises as the Sun is setting. By 9 a.m., Regulus is five fists held upright and at arm’s length above due south, Spica is one and a half fists above the southeast horizon, and Arcturus is three fists above the east horizon.  

Wednesday: Jupiter is opposition tonight. That doesn’t mean that Jupiter is a teenager. Opposition means that Jupiter is on the opposite side of the Earth as the Sun. When an object is in opposition, it is at its highest point in the sky during the darkest time of the day. Thus, opposition is typically the best time to observe a planet. Jupiter is two and a half fists above due south at 1 a.m., midnight non-daylight savings time. If you don’t want to stay up so late, you can see it one and a half fists above due southeast horizon at 10 p.m. If you want to read more about Jupiter, go to https://goo.gl/9fyDcs. If you want to move to Jupiter, you can't. 

Thursday: Mars and Saturn are both two fists above the horizon and on either side of due south at 5 a.m. Mars is a little bit east (to the left) of due south and Saturn is a little bit to the west (to the right) of due south. 

Friday: This weekend, celebrate Mother’s Day with the big mom of the sky, Virgo. Ancient Greeks and Romans associated this portion of the sky with their own goddess of the harvest, either Demeter (Greeks) or Ceres (Roman). Demeter was the mother of Persephone and Ceres was the mother of Proserpina. According to myth, each of these daughters was abducted causing their mothers great grief. The first star in Virgo rises in the afternoon. Spica, the bright bluish star in the constellation rises at 6:30 and is three fists above the south-southeast horizon at 10 p.m. 

The Ellensburg WA sky for the week of 4/28/18

Saturday: As the rock group Journey once thought of singing, “Wheel in the sky keeps on turnin’. Know where the Dipper’ll be tomorrow.” Every night, the Big Dipper and Cassiopeia make a wheel in the sky that turns around the North Star in a counter clockwise direction. Every year on May 3 at 10 p.m., the Big Dipper is straight overhead and W-shaped Cassiopeia is low on the northern horizon. Every year on May 4 at 10 p.m., the Big Dipper is straight overhead and W-shaped Cassiopeia is low on the northern horizon. Every year on May 5 at 10 p.m., the Big Dipper is straight overhead and W-shaped Cassiopeia is low on the northern horizon. Every year on May 6 at 10 p.m., well, you get the idea. Of course, there are subtle charges in the position from night to night. Each northern constellation moves about one degree counter clockwise from one night to the next. But this is not going to change their position in the sky drastically over a few days. So, if you know where the Big Dipper is tonight, you DO know where it’ll be tomorrow. If you are really struggling to understand this concept, Don’t Stop Believin’ in yourself. Just keep studying Faithfully. 

Sunday: Mercury will be as far away from the Sun in the sky as it will get this orbital cycle. This "farthest away" point is known as the planet's greatest elongation. Since Mercury is in morning sky, it is west of the Sun and this occurrence is called the greatest western elongation. This morning, Mercury is just above due east at 5:30 a.m. Over the next few weeks, Mercury will move toward the Sun in the sky. By late June, it will be visible in the evening sky. 

Monday: Winter must be over because the winter constellations are becoming less visible. Orion is setting in the west starting at about 9 p.m. At this time, Orion’s belt is one fist above the west-southwest horizon and Betelgeuse is nearly two fists above the west horizon. By mid-May, Orion will be lost in the glare of the Sun. 

Tuesday: Venus is one and a half fists above the west horizon at 9 p.m. Jupiter has just risen over the east-southeast horizon. By 11 p.m., Jupiter is nearly two fists above the southeast horizon. It looks so peaceful up there. But life is not peaceful for Jupiter. According to a recent study by astronomers, Jupiter gets hit by a 5-20 meter in diameter asteroid 10 to 65 times a year. For comparison, the object that exploded over the Russian city of Chelyabinsk in 2013 was 20 meters in diameter. Earth gets hit by a 20-meter asteroid about once every 50 years. For more information, go to https://goo.gl/RxPc5G.  

Wednesday: At 5 a.m., Saturn is two fists above due south and Mars is one and a half fists to the left of Mars. 

Thursday: The CWU Physics Department and the College of the Sciences is hosting its monthly First Saturday planetarium show this Saturday from noon to 1 pm. CWU physics professor Tony Smith will honor mothers with a presentation about mothers in the night sky. It's certainly not a man's world up there! The show is free and open to all ages. There will be a show at noon on the first Saturday of every month hosted by different CWU astronomers and astronomy educators. The planetarium is room 101 in Science Phase II, just off the corner of 11th and Wildcat Way, H-11 on the campus map found at https://www.cwu.edu/facility/campus-map. 

Friday: The Eta Aquarid meteor shower peaks tonight and tomorrow morning. But since this meteor shower has a fairly broad peak range, there will be many more meteors than in the typical pre-dawn sky throughout the month of May. Meteor showers are named after the constellation from which the meteors appear to originate. The meteors appear to come from a point in the constellation Aquarius near the star Eta. This point is about one fist above the east horizon at 4 a.m. The Moon is in the waning gibbous phase and its light will obscure the dimmer meteors. So you could be rewarded with many bright, fast meteors. The Eta Aquarid meteors slam into the Earth at about 40 miles per second. They often leave a long trail. The Eta Aquarid meteors are small rocks that have broken off Halley’s Comet. For more information about the Eta Aquarids, go to http://earthsky.org/?p=158833. 

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.