SKYLIGHTS
Astronomy news for the week starting Friday, August 18, 2000.
The Moon passes through its last quarter on Tuesday the 22nd
shortly after moonset in North America, thereafter entering its
waning crescent phase. At the same time, it will make lovely
configurations with Saturn and Jupiter, now both stunningly set
amidst the jewel-like stars of Taurus. The morning of Tuesday the
22nd the Moon will appear a bit up and to the right of Saturn,
these two and Jupiter more or less in line. The following morning,
the view gets even better, when Saturn, Jupiter, and the Moon will
make a long, thin triangle, with Aldebaran, the bright star of
Taurus, down and to the left of the lunar disk. The whole affair
is enhanced by the setting among Taurus's two clusters, the Hyades,
which lies in back of Aldebaran (which is not a member of the
cluster), and the Pleiades (or "Seven Sisters"), which now appears
above Saturn.
We are in a period of planetary "bunching," not that that is
anything particularly unusual, at least not over the long haul.
Mercury, the closest planet to the Sun, passes superior conjunction
with the Sun this week on Monday, the 21st, following on the heels
of Venus, which only recently cleared the same configuration. Both
are now on the east side of the Sun, Venus soon to be readily
visible as it climbs out of evening twilight. Jupiter and Saturn
of course are neighborly in Taurus, while the three outer planets,
from west to east, Pluto (in Ophiuchus above Scorpius), Neptune,
and Uranus (both in Capricornus), occupy a 75 degree section of
sky. The three have all been in retrograde, or backward, motion as
a result of the Earth passing them by. That ends this week when
Pluto resumes its direct motion also on Tuesday, the 22nd.
Each day, in response to the Earth going around the Sun, the sky
shifts to the west by a degree, inexorably taking the
constellations from just being visible in morning's dawn to their
eventual disappearance in evening twilight. At 10 PM,
Sagittarius's "Little Milk Dipper is on the celestial meridian, the
sky's north-south line; next week it will be well past it, as the
high Summer Triangle begins to move into that position. Draw a
line from the Triangle's Vega down to the Little Milk Dipper. A
bit to the right of the line's midpoint, and just to the left of
this week's "Star of the Week" (Cebalrai, Beta Ophiuchi), is the
charming "vee" of stars that makes the head of a near-forgotten
"unofficial" constellation, "Poniatowski's Bull," which honors
Stanislas Poniatowski, the last King of Poland.
While admiring the summer sky, look to the star Dscubba, the middle
star of Scorpius's head. It appears to have brightened by nearly
half a magnitude, perhaps in suffering an outburst similar to the
one that affected Gamma Cassiopeiae some 60 years ago.
