The Ellensburg, WA sky for the week of September 30, 2023

Saturday: Since Halloween is a month away, the stores are filled with bags of candy clusters. Use this reminder to take time to look at a star cluster. The Hyades cluster is an open star cluster that represents the V-shaped face of Taurus the bull. It is one of the biggest and nearest star clusters with about 200 stars 150 light years away. The Hyades cluster was the first cluster to be the subject of detailed motion studies. These studies allowed astronomers to pinpoint the distance to the Hyades and provide important information about the scale of the universe. Aldebaran, about one fist held upright and at arm’s length above the east-northeastern horizon at 11:00 p.m., is a foreground star and not a part of the Hyades cluster.

Sunday: Jupiter is less than a half a fist to the lower right of the Moon at 10:00 p.m. They are in the east-northeastern sky. At this time, Saturn is three fists above the south-southeastern horizon.

Monday: Tonight, the Moon is partying with Seven Sisters. The open star cluster called Pleiades, Subaru, or the Seven Sisters is about a finger’s width above the Moon at 9:00 p.m. They are in the east-northeastern sky. 

Tuesday: Coffee. First scientists say it’s good for you. Then they say it is bad for you. Recently, the same argument was applied to an exomoon, a moon orbiting a planet outside our Solar System. No, astronomers are not debating whether exomoons are good for you. Of course they are. But there are conflicting reports over whether the initial exomoon observation shared a year ago was real or just a blip in the data. Astronomers studied the light of a star as a Jupiter-sized planet and then its Neptune-sized moon blocked it. This transit method is one of the most popular ways to observe exoplanets… and maybe exomoons. Read more about the debate at https://www.sciencealert.com/the-first-known-exomoon-is-called-into-question-in-follow-up-studies.

Wednesday: Venus, the brightest point of light in the night sky, is about two and a half fists above the east-southeastern horizon at 6:00 a.m. Regulus, the brightest star in the constellation Leo, is less than a half a fist to the lower left of Venus.

Thursday: Tonight at 6:00 p.m., I’ll give a presentation about solar eclipses at the Hal Holmes Community Center in downtown Ellensburg. There will be educational diagrams, engaging activities, and specific information about the October 14, 2023 annular solar eclipse and the April 8, 2024 total solar eclipse. Both of these eclipses will be partial solar eclipses as seen in Ellensburg. Everyone who attends will get a free pair of solar eclipse glasses for safe eclipse viewing. For more information about the presentation, go to https://www.facebook.com/events/6736370389775583/. For more information about the eclipses, go to https://www.greatamericaneclipse.com/.

Friday: 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.

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 23, 2023

Saturday: “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. Three years ago, astronomers studied data from four earlier missions. They noticed that the light reflecting off the bottom of craters near the lunar South Pole showed characteristics of light reflecting off pure ice. The water likely came from comet impacts or other solar system objects with trace amounts of water ice. This past summer, the Indian Space Research Organization became the fourth country to successfully land on the moon when Chandrayaan-3 landed near the lunar South Pole to study the water there. Read more about it at https://www.space.com/chandrayaan-3-moon-south-pole-why-nasa-wants-to-go-too.

Sunday: Saturn is nearly three fists held upright and at arm’s length above the south-southeastern horizon at 10:00 pm. Jupiter is about one and a half fists above the eastern horizon.

Monday: Ask someone which day in September has the same duration day and night. Go ahead, ask someone. Why are you still reading this? I can wait. If that person says the first day of autumn, they are wrong. Today, three days after the first day of autumn, is the date in which day and night are closest in duration. There are two main reasons for this. First, the atmosphere acts like a lens, bending light from the Sun above the horizon when the Sun is actually below the horizon. This makes the Sun appear to rise before it actually rises and appear to set after it actually sets. Second, fall starts when the center of the Sun passes through the point called the autumnal equinox. But, the Sun is not a point. The upper edge of the Sun rises about a minute before the center of the Sun and the lower edge sets a minute after the center of the Sun. Thus, even if we didn’t have an atmosphere that bends the sunlight, daytime on the first day of autumn would still be longer than 12 hours.

Tuesday: To the people of Ancient Greece, the stars that are about five and a half fists above the northeastern and eastern horizons, respectively, 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.

Wednesday: You discovered Cassiopeia last night. 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. Through binoculars, it looks like a fuzzy patch. At 10:00 p.m., find the star at the top of the sideways “W” known as Cassiopeia. When that star is in the lower left portion of your field of view, Caroline’s Rose is in the center to upper right. For more information about Caroline’s Rose, go to https://stardate.org/radio/program/2020-09-09.

Thursday: 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 simulation 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. 

Friday: At 6:00 a.m., Venus is nearly three fists and Mercury is about a half a fist above the eastern 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 16, 2023

Saturday: Jupiter is two fists held upright and at arm’s length above due east and Saturn is about three fists above the south-southeastern horizon at 11:00 p.m. Jupiter is the much brighter of the two. 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 one and a half “ring diameters” to the side of Saturn at this time. Three of Jupiter’s four largest moons are also visible with a small telescope. Callisto, Io, and Ganymede are on one side of Jupiter, with Callisto appearing the closest and Ganymede the farthest away. Europa is lost in the glare of Jupiter. Recently, astronomers discovered that Callisto’s atmosphere has 1,000 times more molecular oxygen than current models can explain. For more on this, go to https://www.cnet.com/science/space/jupiters-moon-callisto-has-a-whole-lot-of-oxygen-scientists-struggle-to-explain/.

Sunday: Three years ago, 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 life from The Empire Strikes Back but maybe microbial life. Last year, astronomers concluded that the original scientists found the signature of sulfur dioxide, not life. Last year, the private company Rocket Lab published details about the first privately funded mission to another planet - their trip to Venus, The trip was originally scheduled to launch this year but has been delayed to at least 2025. This Venus storyline is an excellent example of science at work. In less than two years, science went from “we may have found a marker for life on Venus” to “it is unclear if we found a marker for life” to “we probably didn’t find a marker for life” to “let’s visit Venus to closely study the thing we thought was a marker for life”. Do an internet search of the words venus and phosphine and read the articles to follow the story. To get yourself in the mood, go outside at 6:00 a.m. Venus is two and a half fists above the eastern horizon at this time. It is the brightest it will be all year. Read more about the potential mission at https://www.space.com/rocket-lab-private-venus-mission-delayed-2025.

Monday: 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 due southwest.

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

Wednesday: The Beehive Cluster is less than a half a fist to the lower right of the waning crescent Moon at 5:00 a.m. They are about three fists above due east.

Thursday: The bright star Sirius is two fists above the south-southeastern horizon at 6:00 a.m.

Friday: At 10:50 p.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 6:49 a.m. and sets at 6:59 p.m. in the northern latitudes of the United States. At these latitudes, day and night are closest to equal duration on Monday.

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 9, 2023

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 catalogs 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: Arcturus is nearly two and a half fists above the western horizon at 9:00 p.m.

Monday: Fomalhaut, the southernmost bright star visible from the northern USA, is one fist above the south-southeastern horizon at 11:00 p.m. In 2008, Fomalhaut and its surroundings became the first star system with an extrasolar planet to be directly imaged. See the family photo at https://apod.nasa.gov/apod/ap081114.html.

Tuesday: While many people think they need a telescope to enjoy looking at the night sky, some objects actually look better through binoculars. Open star clusters are one of those types of objects. M39, the 39th object in Charles Messier’s catalog, is straight overhead at 11:00 p.m. This open star cluster contains about 30 stars in a region about seven light years across and a thousand light years away. A quick trigonometry calculation shows that the cluster is about the same size as the full moon in the night sky. Read more about M39 at https://stardate.org/radio/program/2022-09-04.

Wednesday: Jupiter and Saturn are in the eastern sky tonight at 10:00 p.m.. Saturn is two and a half fists above the south-southeastern horizon and Jupiter is one fist above the eastern horizon. Astronomers discovered volcanoes spewing water vapor on Saturn’s moon Enceladus back in 2005. Just two years ago, scientists published findings of similar activity on Jupiter’s moon Europa. It’s not possible to see Enceladus with a small telescope. But you can see Europa using a small telescope. If you look at 10:00 p.m., you’ll see all four large moons: three on one side and Callisto on the other, about four Jupiter diameters from Jupiter. For more information about Europa’s geysers, go to https://earthsky.org/space/europa-water-vapor-geysers-goddard.  

Thursday: 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 vs. 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.

Friday: Even though tomorrow is Saturday, it is a good morning to get up early. At 6:00 a.m., Mercury is a half a fist above the eastern horizon. The bright star Regulus is nearly a fist and a half above the eastern horizon. Venus, the brightest point of light in the sky, is two and a half fists above the east-southeastern 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.