Saturday:
The earliest sunset of the year occurs throughout the next week: 4:13 p.m. This
seems odd because the shortest day of the year, the winter solstice, isn’t for
about two more weeks. The Sun is at its southernmost point with respect to the
background stars on the day of the winter solstice. This means the Sun spends
the least amount of time above the horizon on that day. But, the sunrise and
sunset times depend on more than its apparent southward motion in the sky. It
also depends on where the Sun is on the analemma, that skinny figure-8 you see
on globes and world maps. During the second week in December, the Sun is not
quite to the bottom of the analemma. But, it is on the leading edge of the
analemma, the first section to go below the horizon. For a slightly different
explanation about this, go to http://goo.gl/kjnHP. Or just go watch the
sunset. But don’t stare at the Sun.
Sunday: Many
Native American Tribes call Tonight’s full Moon the Cold Moon or the Long Night
Moon. Makes sense. You can find it in the constellation Taurus the bull, rising
in the east-northeast sky at 5 p.m.
Monday: Saturn
and Mercury are less than a half a fist above the southwest horizon at 4:45.
Saturn is slightly brighter and to the upper right of Mercury.
Tuesday:
Most constellations don’t look like the object their name refers to. That’s
because most constellations don’t have such a simple to object to emulate as
Triangulum does. Triangulum is shaped like a… wait for it…. Wait for it…. A
thin isosceles triangle. Metallah is the only named star in the constellation.
In Latin this star is called Caput Trianguli, the head of the triangle.
Triangulum is seven fists above due south horizon at 9 p.m. It is pointing down
and to the right with Metallah being the southernmost star at this time of
night. The Triangulum Galaxy can be seen with binoculars about a half a fist to
the right of Metallah.
Wednesday: Earlier
this week, we learned that the early December evenings are getting darker
earlier than any time of the year. While the sky is getting darker earlier, the
nighttime sky is actually getting lighter due to the greater use of low energy
LED bulbs. While these bulbs use much less energy that incandescent or compact
fluorescent bulbs, researchers think that people and communities are using more
of the bulbs and leaving them on longer. This is increasing light pollution
near cities. You can get more illumination on the subject at https://goo.gl/1CdqcH.
Thursday:
It’s getting too cold to see frogs in the wild. Some rich politicians see them
on their dinner plate. But this is a great time to see frogs in the sky.
Ancient Arabs referred to the stars that we now call Fomalhaut and Diphda as
Ad-difdi al-awwal and Ad-difda at-tani. This means the first frog and the
second frog, respectively. Both frogs are low in the southern sky at 7 p.m.
Fomalhaut is one fist above the horizon and one fist to the east of due south.
The slightly dimmer Diphda a little more than two fists above the horizon and
one fist to the west of due south.
Friday: At 7
a.m., dull red Mars is nearly three fists above the south-southeast horizon, about
a half a fist to the left of the slightly brighter, blue-white star Spica.
Jupiter is nearly two fists above the southeast horizon. Venus is just above
the east-southeast horizon.
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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