The Ellensburg, WA sky for the week of September 26, 2020

Saturday:  Mnemonics are helpful for remembering astronomy facts. (Similarly, “Johnny Mnemonic”, the 1995 cyberpunk film, was helpful in getting Keanu Reeves’ career going.) After all, school children around the world are learning the order of the planets by remembering, “My very excellent mother just served us nine….” Oops, I guess that one needs updating. Well, here’s one that will not need updating for tens of thousands of years: the order of the stars in the Big Dipper. Because the nighttime stars are so far away from us, their actual motion through the sky, called their “proper motion” is not noticeable over even thousands of years. That is why the constellations have remained the same since ancient times. But two stars in the Big Dipper have a proper motion large enough such that in 100,000 years; the stars will no longer make a dipper shape. You can see this simulated at the American Museum of Natural History video found at https://youtu.be/sBfUBtdo8yo. Until then, you can remember the names of the seven dipper stars in order from handle to cup by remembering this helpful advice for teens: “AM, ask mom. PM, dad”. The stars are Alkaid, Mizar, Alioth, Megrez, Phad, Merek, and Duhbe. The Big Dipper is one fist held upright and at arm’s length above the northern horizon at 11:00 p.m. 

Sunday: To the people of Ancient Greece, the stars that are about five and a half fists above the east-northeastern horizon at 10:00 p.m. were known as Cassiopeia and Andromeda, a mythological queen and her daughter. But not all cultures imagined the same pictures in the sky. To the people of Polynesia, the stars of Cassiopeia and Andromeda represented a dolphin, called Kwu. Cassiopeia formed its tail, the brightest stars of Andromeda formed its fins, and its fainter stars outlined the dolphin’s body. 

Monday: At 8:00 p.m., Jupiter is two fists above due south. Saturn is a half a fist to the left of Jupiter.

Tuesday: You discovered Cassiopeia two nights ago. The astronomer Caroline Herschel discovered an open star cluster that looks like a rose over 200 years ago. This cluster, called Caroline’s Rose, is about 6,500 light years away and consists of about 1,000 stars that are one third the age of the Sun. For more information about Caroline’s Rose, go to http://tiny.cc/i0zxsz and have the story read to you. Caroline's Rose is five and a half fists above the northeastern horizon at 9:00 p.m. First find the somewhat bright star at the top of the sideways "W" of Cassiopeia. With that star in the lower left portion of your binocular field of view, the Rose is near the center of your field of view.

Wednesday: Venus is two and a half fists above the eastern horizon at 6:00 a.m., trying to earn its nickname as “the morning star”.

Thursday: “There’s water in them thar craters”, frozen water, that is. There has been speculation since the 1960s and indirect evidence since the 2000s of water on the Moon. Two years ago, astronomers studied data from the Moon Mineralogy Mapper, the Lunar Orbiter Laser Altimeter, Lyman-Alpha Mapping Project, and Diviner Lunar Radio Experiment. The light reflecting off the bottom of craters near the lunar South Pole showed characteristics of light reflecting off pure ice in their labs. The water likely came from comet impacts or other solar system objects with trace amounts of water ice. For more information about this discovery, see https://goo.gl/P4zvtU. Tonight’s Full Moon must be full of water because it is in the constellation Cetus the sea monster

Friday: Mars is near the Moon for the entire night. At 8:00 p.m., they are a half a fist above due east, with Mars being a finger width above the Moon. By midnight, the Moon has moved noticeably away from Mars. By tomorrow morning, they are in the western sky. 

Speaking of tomorrow morning, the CWU campus is closed. But astronomy learning lives on! The Physics Department is hosting a First Saturday VIRTUAL planetarium show tomorrow from noon to 1:00 p.m. Former CWU professor Tony Smith will give a show featuring stories and highlights about the stars and planets in the October sky. He will use the browser-based Worldwide Telescope program found at http://worldwidetelescope.org/webclient/. There will be a virtual planetarium show on the first Saturday of every month for the rest of the school year. Stay at home, practice good physical distancing, and visit http://tiny.cc/hpyxsz to register for the show and to attend online using Zoom.

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 September 19, 2020

Saturday: At 8:30 p.m., Jupiter is two fists held upright and at arm’s length above due south. Saturn is two fists to the left of Jupiter. It’s interesting to see them with the naked eye and enlightening to see them in a small telescope. But if you want to see detailed views of Saturn (https://tinyurl.com/y3twzqm3) and Jupiter (https://tinyurl.com/y2b7p5h2), follow the links or go to the Hubble Space Telescope website at https://www.spacetelescope.org. 

Sunday: You see something in the sky so you go through a checklist to identify it.

Red. Check

Bright. Check

Typically in the southern sky. Check

At this point, you and your rival have a debate. You say it is Mars and your rival says it is the red supergiant Antares. That’s fitting because the name Antares means “rival of Mars”. (Ares is the Greek god corresponding to the Roman god, Mars. “Ant-” is a prefix meaning opposite or rival of.) There’s no need to fight tonight because both are visible. Antares is one fist above the southwestern horizon at 8:00 p.m., to the lower left of the Moon. Mars is rising at about this same time and is about two fists above the eastern horizon by 10:00 p.m. For more on Antares, go to

https://skyandtelescope.org/observing/meet-antares-the-star-that-is-not-mars/.

Monday: The bright star Capella is two fists above due northeast at 11:00 p.m.

Tuesday: At 6:32 a.m. PDT, the center of the Sun crosses the celestial equator and passes into the southern sky. The celestial equator is an imaginary line that divides the sky into a northern and southern half. When the Sun is in the southern half of the sky, it appears to take a shorter path from rising to setting. It also does not get as high in the sky at noon. This leads to shorter days and longer nights. Since the Sun crosses the celestial equator today, there is an instant when it is equally in the northern and southern sky, called the north and south celestial hemispheres. This so-called “equal night” is given by the Latin word equinox. Thus, today is known as the Autumnal Equinox. However, the day and night are not of equal duration today. The sun rises at 6:50 a.m. and sets at 6:58 p.m. in the northern latitudes of the United States. At these latitudes, day and night are closest to equal duration on Thursday.

Wednesday: According to “One world, group hug, love everyone” philosophy, political borders are human-made and can’t be seen from space so why can’t we all just get along. According to real world pragmatic discoveries, some human-made political borders CAN be seen from space. Since 2003, India has illuminated its border with Pakistan to prevent illegal crossings. In 2011, astronaut Ron Garan took a picture of that border from the International Space Station. For more information, including the photo, go to http://goo.gl/mY8xG.

Thursday: Earlier this month, astronomers announced that they detected phosphine, a possible biosignature of life, in the upper atmosphere of Venus. Although the surface of Venus is inhospitable, astronomers have long speculated that the upper atmosphere could harbor life. Not Cloud City from The Empire Strikes Back but more like cellular life. There are a few Venus missions in the planning stages for next decade, including a private company that could launch as soon as 2023. To get yourself in the mood, go outside at 6:00 a.m. Venus is about two fists above the eastern horizon. To further enhance your excitement, go to https://skyandtelescope.org/astronomy-news/race-to-venus-how-well-verify-phosphine/. 

Friday: The bright star Vega is about five fists above the western horizon at 11:00 p.m. Its fellow Summer Triangle star Deneb is about two fists above it. Altair, the third star in the triangle, is about four fists above the southwestern horizon.

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 September 12, 2020

 

Saturday: “You know Aries and Cancer and Draco and Libra. Leo and Pisces and Virgo and Hydra. But, do you recall, the pointiest asterism of all? Triangulum, the three sided asterism, had a very pointy shape. And if you didn’t know it, you would say it poked an ape.” Sorry. Some stores have started sending out their Christmas catalogues and that has put me in the mood to modify some Christmas songs. Anyway, Triangulum is a small constellation between the more prominent Andromeda and Aries. Its main feature is a skinny triangle oriented parallel to and nearly four fists held upright and at arm’s length above the eastern horizon at 11:00 p.m.

Sunday: Fomalhaut, the southernmost bright star visible from the northern USA, is one fist above the south-southeastern horizon at 11 p.m. In 2008, Fomalhaut and its surroundings became the first star system with an extrasolar planet to be directly imaged  https://apod.nasa.gov/apod/ap081114.html. 

Monday: The waning crescent Moon, Venus, and the Beehive Cluster make a small triangle in the sky this morning. They are about two and a half fists above due east at 5:30 a.m. The Beehive Cluster, described by Ptolemy as “a nebulous mass in the breast of Cancer [the crab]”, is about a thumb-width above Venus.

Tuesday: Jupiter and Saturn are about two fists above due south at 9:00 p.m. Jupiter is the much brighter of the two. Saturn is about a fist to the left of Jupiter. When you are looking at this part of the sky, you are looking in the direction of more than just the two planets. You are also looking in the direction of their moons. Titan, Saturn’s largest moon, is easily visible with a small telescope, about five “ring diameters” to the side of Saturn at this time. Jupiter’s four largest moons are also visible with a small telescope. Callisto and Ganymede are on one side of Jupiter, with Ganymede appearing the farthest away. Europa is visible in the other. If you have very clear skies, you may see Io on the Europa side, right next to Jupiter. Recently, a team of Canadian astronomers analyzed images of Jupiter from 2010 and estimated that Jupiter could have 600 moons at least 800 meters, a half mile, in diameter. They didn’t actually discover these moons. They just formulated a possible model of the Jovian system. For more on this, go to https://skyandtelescope.org/astronomy-news/jupiter-could-have-600-moons/. 

Wednesday: In 1987, the rock group Def Leppard sang “Pour some sugar on me, in the name of love. Pour some sugar on me, come on fire me up”. In 2012, some European astronomers “found some sugar near stars, they were very young. Found some sugar near stars, out where planets formed.” Astronomers observed molecules of glycolaldehyde, a simple form of sugar, in the disk of gas and dust orbiting young binary stars. This is the first time astronomers have found this simple sugar so close to a star indicating that organic molecules can be found in planet-forming regions of stars. For more information, go to http://goo.gl/tfwy1.

Thursday: Mars is about two fists above the eastern horizon at 11:00 p.m.

Friday: Earlier this week, you read about Fomalhaut, the second brightest star with a planet. The brightest star known to have a planet is Pollux, in the constellation Gemini. (First and second brightest is meaningless here because they are nearly identical in magnitude, 1.15 vs. 1.16.) Pollux is four and a half fists above due east at 5:30 a.m., right below its “twin” star Castor.  Read more about Pollux at https://goo.gl/cL5t9p.

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 September 5, 2020

 

Saturday:  Mars is about one thumb-width above the Moon at 10:00 p.m., one fist above the eastern horizon. They hang out together the entire night. By 6:00 a.m., they have shifted to the southwestern sky with Mars now being to the lower right of the Moon.

Sunday: “Excuse me, do you have the time?”

“No, but the Big Dipper does.”

You can use the orientation of the Big Dipper to tell time with a precision of about 15-30 minutes. First, find the two stars at the far end of the Big Dipper cup, the stars that do not touch the handle. Draw an imaginary line segment starting at the North Star and passing through the two Big Dipper cup stars. Now, draw a big circle around the North Star. Your circle is a 24-hour clock. Number the circle from 0 hours at the top, counterclockwise to 12 hours at the bottom of the circle, and back up to 24 hours at the top. (O hours and 24 hours are the same on this clock because the day is 24 hours long.) The hour number on the big circle closest to where your imaginary line intersects this circle is called your raw time. Due to the location of the Big Dipper compared to the rest of the stars, the time nearest the intersection (the raw time) is correct for March 6. For any other night, subtract two times the number of months the current date is after March 6 from the raw time. For example, let’s say the imaginary line between the North Star and the Dipper stars is pointed to the right. That means the raw time is 18 hours or 6 p.m. If you made this observation tonight, which is six months after March 6, you would subtract two times six or 12 hours from the raw time.  Don’t forget to convert for daylight savings time if needed. For a more complete explanation on how to do the Big Dipper clock math, go to http://goo.gl/02HmA. If you prefer a more visual tool, and a fun project to do with your kids, there is a simple “star clock” template and instructions at https://skyandtelescope.org/observing/make-a-star-clock/. Use this paper star clock whenever your watch is broken. The Big Dipper is in the northwestern sky at 9:00 p.m. tonight.

Monday: Labor Day was the brainchild of labor unions and is dedicated to American workers. The first Labor Day was celebrated in 1882. The Greek mythical hero Hercules probably wished there was a Labor Day to commemorate his work. As punishment for killing his family while he was temporarily insane, he had to perform twelve nearly impossible tasks such as killing monsters or stealing things from deities. Hmmm. Maybe we shouldn’t commemorate his labors. But we can enjoy his constellation. The keystone asterism representing the body of Hercules is six fists held upright and at arm’s length above the western horizon at 10:00 p.m. For more information about the Labors of Hercules, go to http://goo.gl/ozVF5. 

Tuesday: School starts this week so it is time for a little geometry review. A square is a regular quadrilateral. This means it has four equal sides, four equal angles, and wears old fashioned clothing. Go outside at 10:00 p.m. tonight with a notebook in hand to sketch one. The Great Square of Pegasus is balancing on its corner three fists above the eastern horizon. The top corner of the square is two fists above the bottom corner. The other two corners are to the left and right of the line segment connecting the top and bottom corners. 

Wednesday: Fomalhaut, the southernmost bright star, is one fist above the south-southeastern horizon at 11:00 p.m.

Thursday: Geometry review, part 2. Go outside at 10:00 p.m. tonight with notebook in hand. (Good teaching involves a little repetition.) A triangle is a polygon with three corners and three line segments as sides. A good example is the Summer Triangle made up of the bright stars Vega, Deneb and Altair. Altair is five fists above the southern horizon. Vega, the brightest star in the triangle, is seven fists above the western horizon. Deneb is a little bit east of straight overhead.  

Friday: See Jupiter two fists above due south at 9:00 p.m. Saturn is less than a fist to the left of Jupiter. Now go to bed. Then get up to see Venus three fists above the east horizon at 6:00 a.m.

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.