Skylights featured five times on Earth Science
Picture of the Day: 1
, 2
, 3
, 4
, 5
Photo of the Week.
Cloud shadows and fingers of sunlight proclaim the glory of the sky.
Astronomy news for the two-week period starting Friday, March
17, 2006.
Read A
Minute with Jim Kaler, a brief interview on the outer bodies of
the Solar System that appears on the U of I home page.
Skylights will next appear on Friday, March 31.
The fortnight sees the Moon in its waning stages, beginning with
the waning gibbous. Passing third
quarter on Wednesday, March 22, the Moon then goes to the waning crescent, finally passing new
on Wednesday the 29th. You might then get a glimpse of it as a
slim waxing crescent in evening
twilight the night of Thursday the 30th.
Look for the Moon to the south of Jupiter the
morning of Sunday the 19th, then see it to the west of Antares in Scorpius the morning of Monday the 20th and to the east
of the red supergiant
the following morning. The morning of Saturday the 25th, the Moon
not only passes, but occults Ceres, the
largest asteroid (the event sort of visible only on the east
coast). The better target is Venus, the Moon to
the southwest of the brilliant planet the same morning (the 25th),
while to the southeast of it the following dawn. On the 25th and
the 27th, it also respectively moves to the south of Neptune, then Uranus, the two
outer planets having both moved into the morning sky. Finally, you
might see it to the right of Mercury in dawn the morning
of Monday the 27th.
Coupled to the penumbral eclipse of the last full Moon is a total eclipse of the Sun at the time of new Moon, on
Wednesday the 29th, but one that will sadly miss all of North
America, as the path runs from eastern South America then across
Africa, southern Europe, and central Asia.
We fare better with the planets, as Venus
reaches its greatest western elongation 47 degrees to the west of
the Sun on Saturday the 25th, the brilliant body rising around 4
AM, half an hour before the onset of twilight. At almost the same
time, Saturn -
- nicely visible in Cancer and high
to the south at 8:30 PM -- sets. Rising ever earlier, Jupiter
(still in Libra) now comes on the
scene around 10 PM, while transiting the meridian as dawn
approaches, about an hour before Venus rises. Finally, look for Mars (in Taurus) to the west as the sky
darkens, the red planet still not setting until after midnight.
The biggest planetary news is of planet Earth. At 12:26 PM Central
Time (1:26 PM EST, 11:26 AM MST, 10:26 AM PST) on Monday, March 20,
the Sun passes the Vernal Equinox
in Pisces, which begins spring in
the northern hemisphere, fall in the southern. On that day, the
Earth's axis is perpendicular to the line to the Sun, the Sun is overhead
at the Earth's equator, and rises due east and sets due west. Days
and nights are also closely equal at 12 hours apiece, and ignoring
refraction in the atmosphere and the finite diameter of the Sun,
the Sun rises at the north pole and sets at the south pole to
initiate the long south polar night.
While not on everyone's lips (except for those watching the
television program "Jeopardy," which recently featured it in a
question), this is a fine time of year to admire (as best you can),
Monoceros, the Unicorn, which lies
to the east of Orion and between
Sirius and Procyon. While seeming to be a
rather blank area of sky, Monoceros, falling in the faint
winter Milky Way, is filled with
fascinating young stars and nebulae, and is a rich ground for the
dedicated amateur star gazer.
