Skylights featured five times on Earth Science
Picture of the Day: 1
Photo of the Week. Mars! As you would see it
through a telescope from Earth (though right side up, not inverted
as a telescope would do). The dark wedge to the upper left is the
wind-swept volcanic plain Syrtis Major, the bright spot to the
lower left of it Hellas, a huge impact basin. Photo by Mark
Astronomy news for the week starting Friday, November 18, 2005.
Skylights now resumes its normal weekly schedule.
A happy Thanksgiving
The Moon begins our week in its waning gibbous phase, then passes through third
quarter on Wednesday, November 23, after which it wanes through
crescent. That same morning it goes through apogee,
where it is farthest from the Earth. The night of Saturday the
19th finds the Moon positioned beautifully to the south (to the
right at rising) of Castor and Pollux in Gemini, making a fine triangle with them. Watch then
as the near-quarter plows north of Saturn the
night of Monday, the 21st.
Speaking of which, Saturn (now rising around 10 PM) passes a
milestone on Tuesday the 22nd.
In Cancer to the
southeast of the Beehive
Cluster, the ringed planet stops its slow easterly motion
against the stars and begins its western retrograde" as the Earth prepares
to pass between it and the Sun. The only other
planetary events involve Mercury,
which quite invisibly passes to the north of Antares in Scorpius (in very bright western twilight) on Friday
the 18th, and then goes through inferior conjunction with the Sun
(more or less between us on and Sun) on Thursday the 24th.
We don't need "events" to admire the planets, however. Look for
brilliant Venus way to
the southwest after sundown. Now in Sagittarius, the planet does not set until nearly an
hour and a half after the end of twilight. A telescope will show
the planet in a fat crescent stage (in which we see more nighttime
than daylight) as it slowly moves to pass between us and the Sun.
On the flip side, in the morning just before dawn, watch for the
rising of Jupiter
around 5 AM as Saturn transits the meridian and just before Mars (in the
middle of it all) sets. The red planet, having just passed its
opposition to the Sun, is now dramatically obvious to the east in
early evening and outshines everything except Venus.
The northern sky is especially grand this time of year. In mid-
evening the "W" of Cassiopeia (the
celestial Queen) rides high above the sky's north rotation pole (and Polaris). This much-loved figure is
sandwiched between the much dimmer figure of Cepheus (the King) to the
northwest and glorious Perseus to
the southeast, the Hero highlighted by streams of stars. South of
Cassiopeia lies her mythological daughter, Andromeda, which contains the
Galaxy, M 31. At a distance of some 2.4 million light years,
this smudge of light is the farthest thing you can see with the