SKYLIGHTS
Astronomy news for the week starting Friday, August 24, 2001.
The Moon passes through its first quarter early in the week, on
Saturday, the 25th, thereafter waxing toward its full phase,
brightening as it goes through Scorpius and Sagittarius, bottoming
out at its most southerly position of the month the night of
Tuesday, the 28th. The night of Saturday, the 25th, the Moon will
pass 12 degrees north of Antares in Scorpius, while the following
night it will be approaching its passage to the north of Mars. The
night of Thursday the 30th, it is Neptune's turn to be visited.
Mars is now transiting the meridian to the south in bright
twilight; by darkness it has moved into the southwest, where, as
seen in the early evening, it will remain throughout the year. For
observers in the mid-northern hemisphere, setting time has moved to
just after midnight daylight time. But as Mars prepares to set,
Saturn rises in the northeast, followed around 2 AM by Jupiter,
which has now pulled rather far to the west of Venus, the brilliant
"morning star" rising before the onset of twilight until the end of
October (by which time Saturn and Jupiter will be rising in early-
to-mid evening).
Not that anyone will notice, but Pluto ceases its westerly
retrograde movement against the stars of southern Ophiuchus this
week, on Saturday the 25th. Three days later, Ceres, the largest
asteroid (570 miles -- 910 kilometers -- wide and also invisible
without a telescope), does the same thing. The orbits of asteroids
are commonly more highly tilted than are those of the planets
(Pluto excepted). Ceres, now beneath the Little Milk Dipper in
Sagittarius, is about as far south as it gets, some 8 degrees below
the ecliptic (the apparent path of the Sun).
As August heads towards September, the sky's fifth brightest star,
Vega in Lyra, passes nearly overhead in early evening for those in
mid-northern latitudes. A bit farther north (and a bit west) is
the much fainter head of Draco, the Dragon. A line drawn south
from Vega passes through the line of stars that makes the tail of
Serpens the Serpent (the only constellation that comes in two
parts, the head and tail divided by Ophiuchus), then much farther
down back to Sagittarius, which sits atop Corona Australis, the
Southern Crown. Once the Moon gets out of the way, you can admire
the great star clouds of the Milky Way that seem to blanket
Sagittarius, the celestial archer, one of two mythological centaurs
in the sky, the other Centaurus, a much larger constellation now
escaping to the west, its southern portions far below the horizon
for most people in the northern hemisphere.
