Saturday: Mercury and Venus, the brighter of the two, are about a half a fist above the western horizon at 8:00 p.m.
Sunday: 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 10:05 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.
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, a few
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 already 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: 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 28 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 28 moons. 25 of Uranus’ moons are named after characters in
works by William Shakespeare and three are from the poem “The Rape of the Lock”
by Alexander Pope. Uranus is two and a half fists above due west at 9:30 p.m.
It is a half a fist below the Pleiades open star cluster.
Wednesday: At 8:30 p.m., Mars is nearly seven fists above
the southern horizon and Jupiter is five fists above the west-southwestern
horizon.
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 1:59 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.
Friday: 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 to observe the Sun’s corona as well as
solar system objects that pass near the Sun. For the next few days, 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/.
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.
All times are Pacific Time unless noted.
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