The Ellensburg, WA sky for the week of March 28, 2020

Saturday:  Venus is at its brightest this orbital cycle. You can’t miss it, three and a half fists held upright and at arm’s length above the western horizon. Comet Atlas is not at its brightest yet. That time will come in mid- to late May. For now Comet ATLAS (C/2019 Y4) is making its way into binocular range. At 9:30 p.m., it is six and a half fists held upright and at arm’s length above the northern horizon and two fists above the North Star. The easiest way to find it with binoculars is to first center on the North Star and then move your binoculars straight up, about two or three binocular fields of view for typical 10X50 binoculars. If you have a super fancy app, search for a star called HR 3182. It will be in the same binocular field of view as that.

For more information about the comet, and a basic map on how to find it over the next month, go to https://skyandtelescope.org/astronomy-news/comet-atlas-will-it-become-a-naked-eye-object/. 

Sunday: Aldebaran and the Hyades Cluster are one fist below the crescent Moon, three fists above the western horizon at 9:00 p.m. The stars in the Hyades Cluster are all young, as stars are judged, formed in the same cloud of gas and dust a few hundred million years ago. But just as children move away from home, the stars of the Hyades Cluster are slowly drifting apart. Millennia from now, future sky watchers will see these stars as random points of light in the sky and not as a family. I hope they at least call home every so often. For more information, go to https://www.skyandtelescope.com/astronomy-news/end-hyades-star-cluster/.

Monday: Mars and Saturn are about a thumb width apart from each other with Mars looking slightly reddish and Saturn looking slightly yellowish. (Is that even a word?) The much brighter Jupiter is less than a fist to the east of them. All of them are one fist above the southeastern horizon at 6:00 a.m.

Tuesday:  Global Astronomy Month starts tomorrow with a kickoff Facebook Live event at 10:00 a.m. Pacific Daylight Time. Project coordinators from different parts of the world will talk about what is happening in astronomy in their region. The first big virtual observing event is Friday morning, viewing Venus in the Pleiades. For more information and a schedule of events, go to

https://astronomerswithoutborders.org/gam2020-programs/program-schedule-2020.html.

Wednesday: The Milky Way is pretty easy to spot on the early spring sky. Just look up. Everything you see in the sky, including that bird that just startled you, is in the Milky Way. But, even the path of densely packed stars in the plane of our galaxy that look like a river of milk is easy to find. Face due west at 9:00 p.m. in a fairly open area. The fuzzy Milky Way path starts due south, moves upward past the bright star Sirius, towards the bright star Capella, through W-shaped Cassiopeia and down to due north where the bright star Deneb sits just above the horizon.

Thursday: Last night you looked at something fuzzy. So reward yourself tonight by looking at something sharp and detailed. The OSIRIS-REx mission has just sent back the highest resolution global map of any Solar System object, the asteroid Bennu. Using pictures taken from just three to five kilometers above the surface, the map has a resolution of five centimeters per pixel. For more information about the mission, as well as the detailed images, go to https://www.asteroidmission.org/.

Friday: It is often said that Earth is a water world because about 70% of the Earth’s surface is covered by water. What would it look like if all that water on the surface were gathered up into a ball? That “ball” would be about 700 km in diameter, less than half the diameter of the Moon. The Astronomy Picture of the day shows us right here https://apod.nasa.gov/apod/ap120515.html.

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 March 21, 2020

Saturday:  Many artists have sung the song “Blue Moon”. But few have sung the song “Blue Planet”. It goes, in part “Blue Planet, you saw me standing with 27 others. Rolling around like a barrel. Without close sisters or brothers.” It’s about the planet Uranus, which orbits the Sun in a rolling motion and has 27 moons. Every one of Uranus’ moons is named after characters in works by William  Shakespeare or Alexander Pope. Uranus is one and a half fists held upright and at arm’s length above due west at 8:30 p.m., easily visible with binoculars. First find Hamal and Sheratan, two stars of similar brightness, two fists above the west-northwestern horizon and stacked vertically a half a fist apart from each other. Then move your binoculars straight left from Sheratan to a 19 Arietis, a star about one tenth as bright but still the brightest in the field of view. With 19 Arietis at the top of your field of view, Uranus will be near the center. Return to this same spot for the next few nights. If the point you are looking at moves compared to the neighboring points of light, you are looking at Uranus.

Sunday: Has there ever been life on Mars? Astronomers don’t know. But the Mars Curiosity Rover has been digging up some strong evidence that Mars was hospitable to life in the past. At the end of 2012, the first drilling assignment for Curiosity found clay-like minerals that form in the presence of water. In December 2013, scientists announced the strongest evidence yet for an ancient fresh-water lake in Gale Crater. Planetary geologist John Grotzinger said that Earth microbes would have thrived in this lake if they were placed there. Last year, astronomers at the European Southern Observatory’s Very Large Telescope in Chile found evidence that Mars once had an ocean that held more water than the Arctic Ocean and covered a greater percentage of Mars’ surface than the Atlantic Ocean does on Earth. Finally, November 2018, the InSight mission landed on Mars and almost immediately started digging to study the geology of Mars. While geology isn’t life, many scientists think there is a relationship between geologic activity and the favorability for life to evolve. In pop culture news, NASA just names a small rock on Mars Rolling Stones Rock after the legendary band. For more on Rolling Stones Rock, go to https://go.nasa.gov/MarsRocks. See Mars one fist above the southeastern horizon at 6:00 a.m. Over the next few days it will move away from bright Jupiter in the sky and towards Saturn.

Monday: 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 the morning sky, it is west of the Sun and this occurrence is called the greatest western elongation. This morning, Mercury is a half a fist above the eastern at 6:30 a.m. Over the next few weeks, Mercury will move toward the Sun in the sky. By late May, it will be visible in the evening sky.

Tuesday: This evening, Venus is as far away from the Sun in the sky as it will get this orbital cycle, known as the planet’s greatest eastern elongation. Tonight is one of the best nights of the year to observe Venus because it is far from the Sun at sunset. Venus is three fists above due west at 8:30 p.m. Over the next two months, Venus will move toward the Sun in the sky and get closer to the horizon. By early June, it will be lost in the glare of evening twilight.

Wednesday: The bright star Arcturus is three and a half fists above the eastern horizon at 11:00 p.m.

Thursday: Saturn, Mars, and Jupiter make a line in the early morning sky. Jupiter is one and a half fists above the south-southeastern horizon. Reddish Mars is less than a half a fist to the lower left of Jupiter and yellowish Saturn is less than a half a fist to the left of Mars.

Friday: April is Global Astronomy Month (GAM). While many astronomy experiences come from using your eyes, you can also experience astronomy with your ears and your hands. GAM has numerous arts initiatives including a Cosmic Concert and an AstroCrafts Project. Go to https://astronomerswithoutborders.org/gam2020-programs/program-schedule-2020.html for more information about events.

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 March 14, 2020

Saturday:  Avast ye matey. Swab the poop deck. Pirates love astronomy. In fact, the term “poop” in poop deck comes from the French word for stern (poupe) which comes for the Latin word Puppis. Puppis is a constellation that represents the raised stern deck of Argo Navis, the ship used by Jason and the Argonauts in Greek mythology. Argo Nevis was an ancient constellation that is now split into the constellations Puppis, Vela and Carina. The top of Puppis is two fists above due south and about a fist and a half to the left of the bright star Sirius at 9:30 p.m. Zeta Puppis, the hottest, and thus the bluest, naked eye star in the sky at 40,000 degrees Celsius, is about a half a fist above due south at this time..

Sunday: Venus is more than three fists above the western horizon at 8:00 p.m.

Monday: Ask someone which day in March has the same duration day and night. Go ahead, ask someone. Why are you still reading this? I can wait. If that person said the first day of spring, they are wrong. Today, four days before the first day of spring, is the date in which day and night are closest in duration in central Washington. 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, spring starts when the center of the Sun passes through the point called the vernal 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 spring would still be longer than 12 hours.

Tuesday: “Oooo, they’re little runaways. Orion’s stars moved fast. Tried to make a getaway. Ooo-oo, they’re little runaways,” sang Bon Jovi in his astronomical hit “Runaway.  At least that’s what I hear when I listen to the song. After all, it fits the recently calculated trajectory of AE Aurigae, Mu Columbae, and 53 Arietis. Extrapolating the actual motion of these three stars back in time, they were all in the location of the star-forming region called the Orion Nebula a few million years ago. What kicked these stars out? Not paying rent? Excessive partying? No, it was simply gravitational interactions with near-by stars. Find out more about the eviction at http://goo.gl/UeLwKQ. The Orion Nebula is visible with the naked eye from a very dark site, about three fists above the southwestern horizon at 9:00 p.m.

Wednesday: The southeastern sky is crowded with Solar System objects this morning at 6:00. Most noticeable is the waning crescent Moon, a fist above the southeastern horizon. The bright planet Jupiter is less than a half a fist above the Moon. Mars is about a finger width to the right of Jupiter. Saturn is a little more than a half a fist to the left of the Moon.

Thursday: Look up in the sky. It’s a plane. It’s a bird. No, it’s the vernal equinox. The vernal equinox!? Spring starts at 8:54 p.m. Pacific Daylight Time. The first day of spring is often called the vernal equinox. This label for the day is misleading. The vernal equinox is actually the point in the sky where the Sun’s apparent path with respect to the background stars (called the ecliptic) crosses the line that divides the stars into northern and southern celestial hemispheres (called the celestial equator). This point is in the constellation Pisces the fishes. At the vernal equinox, the Sun is moving from the southern region of background stars to the northern region. 

Because the Earth slowly wobbles like a spinning top, the vernal equinox is slowly moving into the constellation Aquarius. By the year 2597, the vernal equinox will reach the constellation Aquarius and the “Age of Aquarius” will begin. Until then, we’ll be in “the age of Pisces”.

Friday: If you want to put somebody off, tell her or him to wait until Deneb sets. At Ellensburg’s latitude of 47 degrees, Deneb is a circumpolar star meaning it never goes below the horizon. At 9:45 p.m., it will be as close as it gets to the horizon, about two degrees above due north. Watch it reach this due north position about 4 minutes earlier each night.

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.