The Ellensburg, WA Sky for the week of March 20, 2021

Saturday:  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 2:40 a.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”.

Sunday: 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. With Sheratan at the right side of your field of view, there will be a small triangle pointing upward on the left side of your field of view. Now move your binoculars until the triangle is on the right side of your field of view. Uranus will be near the left side of your field of view. 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.

Monday:  If you know exactly where to look in the sky, you can see a few bright planets when the Sun is out. The Solar and Heliospheric Observatory, or SOHO, is always watching the sky when the Sun is out… because it is always watching the Sun! Most of the SOHO images are filtered images of the Sun’s photosphere, the top of the visible layer. But two images, the LASCO C2 and C3, place a mask over the Sun in order to observe the Sun’s corona as well as solar system objects that pass near the Sun. For the next few days, Venus passes right below the Sun and is visible in one or both of the LASCO images. It is the bright spot with the long streak on either side due to overexposure. For more about using SOHO to observe Solar System objects, go to https://skyandtelescope.org/astronomy-news/planets-and-comets-cant-hide-from-sohos-eye/.

Tuesday: 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 9:35 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.

Wednesday: The Perseverance Rover landed on Mars a few weeks ago to look for evidence of past life in the rocks and regolith. In November 2018, the InSight mission landed on Mars and also 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. When InSight landed, its thrusters pushed a small rock along the ground. Astronomers named that rock Rolling Stones Rock after the legendary band. For more on Rolling Stones Rock, go to https://go.nasa.gov/MarsRocks. Mars is about four and a half fists above the western horizon at 9:30 p.m. 

Thursday: Regulus is a half a fist to the lower right of the Moon. They are five fists above the southeastern horizon at 9:30 p.m.

Friday: Global Astronomy Month (GAM) starts next week. While many astronomy experiences come from looking at something, you can also experience astronomy by creating something. GAM has numerous arts initiatives including AstroArts and AstroPoetry. Go to https://my.astronomerswithoutborders.org/programs/global-astronomy-month 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.