Skylights featured three times on Earth Science
Picture of the Day: 1
, 2
, 3
, 4
.
Photos of the Week.. Algol, the bright eclipsing double
star in Perseus, is the brightest
star in the left-hand half of each picture. In the photo at left,
the star is in its normal unellipsed state. In the photo at right,
the star is at mid-eclipse (the fainter component partly in front
of the brighter one) and is notably dimmer, as can be seen by
comparing it with other stars in the field of view. These images
are now in Algol's updated story on Stars.
Astronomy news for the week starting Friday, November 12, 2004.
The week belongs to the waxing
crescent Moon. We begin on Friday, November 12, with the new
Moon and end the night of Thursday the 18th with the first
quarter, the phase taking place around the time of Moonset in
North America. The slim crescent will first be visible in the
southwest the evening of Saturday the 13th. With the Sun over
halfway from the Autumnal
Equinox to the Winter Solstice,
the crescent will be swinging low through the southern
constellations of the Zodiac such
that the first quarter will be seen near the Capricornus-Aquarius
border. Waxing along, Earthlight on the nighttime side gradually
fading away, the Moon will pass Mercury the night of Saturday the
13th, though the little planet will be quite difficult to see in
bright twilight. The Moon actually occults, or passes in front of,
Mercury,
but only from the ice cap of
Antarctica. On the night of Wednesday the 17th it passes well
to the south of
Neptune in Capricornus. Just two days after new Moon, our
satellite will pass perigee, where it is closest to the Earth in
its monthly round.
Aside from elusive Mercury, the ancient planets (those known since
ancient times) have but one evening representative, Saturn
, which is now rising in eastern Gemini around 9 PM. A telescope at 40 power or above
reveals the planet's magnificent ring
system. All the big planets have rings (disks made of finely
divided icy debris), but none like Saturn (those of
Jupiter,
Uranus, and
Neptune dark and very hard to see).
Planetary glory really belongs to the morning sky, where Venus
and
Jupiter rule together in their brilliance. Following their
November 4 conjunction, Jupiter has steadily moved to the west of
Venus, and now rises about 3 AM, roughly an hour before Venus. A
telescope quickly reveals up to four of
Jupiter's moons (which can actually be seen in binoculars) and
Venus's gibbous shape. On the morning of Tuesday the 16th, Venus
will pass four degrees to the north of the first magnitude star Spica in Virgo. An hour after Venus rises, just before the
beginning of twilight, up comes much dimmer reddish Mars
The Leonid meteor
shower traditionally peaks the morning of November 17, but the 19th will
see some action too, though not as great as in years past.
Beautifully climbing the eastern sky at sundown are the classic
constellations of northern Autumn. By late evening Cassiopeia -- noted by the upside-down
"W" -- is nearly overhead, Andromeda to the south, while the northeast is graced
by the star streams that make Perseus, the Hero and rescuer of Andromeda. Following
well behind Perseus, lighting up the far northeast in late evening,
is Capella in Auriga, the most northerly of the
set of first magnitude stars.
