Saturday: Venus is a half a fist held upright and at arm’s length above due west 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 10:15 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: 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 10:00 p.m.
It is half a fist below the Pleiades open star cluster.
Tuesday: 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. Go to https://www.timeanddate.com/sun/ to
find the day for your city. It will be close to today for all USA cities.
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.
Wednesday: Jupiter is six and a half fists above the
south-southwestern horizon at 9:00 p.m.
Thursday: 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, 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, including comets. For more about using
SOHO to observe comets, go to
https://www.youtube.com/watch?v=K8yUa8_EAUc.
Friday: 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 7:45 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.
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.