Saturday: 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 all around the country 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 nearly 100,000 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 than in
100,000 years; the stars will no longer make a dipper shape. 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 north horizon at 11 p.m.
Sunday: Venus
and Mars are about a pinky width apart, one and a half fists above the east
horizon at 6:30 a.m. That’s pretty close. But, they will get closer later in
the week. By Thursday morning, they’ll be less than the apparent diameter of
the full Moon apart from each other.
Monday: Say
“good bye” to Jupiter because it will soon be lost in the glare of the Sun for
a few weeks. It is less than a half a fist above the west-southwest horizon
right after sunset.
Tuesday: Since
Halloween is later this month; the stores are filled with bags of candy
clusters. Instead, 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, nearly two fists held upright and at arm’s length above
the east horizon at 11 p.m., is a foreground star and not a part of the Hyades
cluster.
Wednesday: Speaking of good byes, NASA said “good bye” to the Cassini
spacecraft earlier this month. This picture (https://stardate.org/astro-guide/gallery/saying-goodbye)
shows Cassini saying “good bye” to the moon Enceladus as it plunges into
Saturn’s atmosphere. Say “Hello”
to Saturn at 7:30 tonight, one and a half fists above the south-southwest
horizon.
Thursday: Get up at 6:30 a.m., dig a dime out of your piggy bank, and hold
it out at arms length, one and a half fists above the east horizon. You’ll be
able to block both Mars and Venus at the same time. That’s how close together
they are in the sky. Winter is coming to the morning sky. The “winter
constellations” such as Orion, Taurus, and Gemini are high above the southern
horizon at 6:30 a.m. They are called winter constellations because they are
high in the sky during the evening viewing hours of the winter months.
Friday: To
the people of Ancient Greece, the stars that are about five and a half fists
above the east-northeast horizon at 10 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.
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.
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