Skylights featured three times on Earth Science
Picture of the Day: 1
, 2
, 3
, 4
.
Photo of the Week.. A spectacular diffraction corona
surrounds the Moon, caused by diffraction of moonlight through
light clouds, the same phenomenon that makes the colors in a
compact disk.
Astronomy news for the week starting Friday, February 4, 2005.
A belated Happy Groundhog Day (February 2) to everyone. An
astronomical "holiday," Groundhog Day is one of the four
"cross-quarter days" that split the differences between the
passages of the Sun over the equinoxes
and the solstices. We are halfway to spring (in the northern
hemisphere).
We start the week with the waning
crescent Moon in the morning sky, as it goes toward its new
phase, with the Moon between us and the Sun, on Tuesday, February
8. By the night of Wednesday the 9th, if you are lucky you might
get to see the very thin waxing crescent in the southwestern
evening twilight sky. By the night of Thursday the 10th, you will
not have to look as such, as the Moon -- in twilight -- will be
pretty obvious. Then, and over the following few nights, it will
present a beautiful sight, as its nighttime side will be aglow with
Earthlight, with light reflected
from (from the point of view of the Moon) the nearly-full Earth.
Almost exactly one day before the Moon passes new, on Monday the
7th, it runs through perigee
, which will make for nicely high (and especially low)
tides at the coasts (not an issue in the Midwest).
The morning of Friday the 4th the waning
crescent was just to the east of Antares in Scorpius. The following morning, that of Saturday the
5th, the even thinner Moon will pass four degrees south of Mars, which is now
to the northwest of Sagittarius.
Mars, however, pales next to
Jupiter, which dominates the morning sky, the planet now in
retrograde and up and to the right of Spica in Virgo. Ever so slowly the giant planet is moving into
the evening sky. Now rising around 10:30 PM, it is rather well to
the west of the meridian as dawn lights the morning. Jupiter and
its brother planet
Saturn -- the two of similar size and construction -- are
working in a sort of synchrony. Saturn now rises well before
sunset and is nicely up in the northeast as twilight darkens the
sky, and for the next month or so, it crosses the meridian just as
Jupiter rises.
Watch Auriga, the ancient
Charioteer, cross the sky nearly overhead in mid-northern
latitudes. The constellation, halfway around the pole between the
Big Dipper and Cassiopeia, is one of the most
prominent of northern constellations, its luminary Capella the most northerly of first
magnitude stars. Plunge southward and you pass through Taurus (with bright Aldebaran), Orion (with Betelgeuse and Rigel), Lepus (the Hare), and Columba (the Dove). Auriga's positional counterparts
in the deep southern hemisphere, far to the south of Orion, are
(roughly) Pictor, the Easel, and Dorado, the Swordfish, modern
constellations that are much too far south to be seen from ancient
northern lands. Dorado contains one of the most remarkable objects
of the sky, the Large
Magellanic Cloud, a nearby satellite galaxy 150,000 light years
away.
