SKYLIGHTS
Astronomy news for the week starting Friday, October 2, 1998.
The Moon grows through its gibbous phase this week to full on
Monday, the 5th, this full Moon, like the one in September, also
called the "Harvest Moon" as it is the closer to the time of the
autumnal equinox, but also the "Hunter's Moon" as it occurs in
October. Frost is not far off now as the Sun glides slowly to the
south along the ecliptic path, rising ever later, setting ever
earlier, crossing the sky ever lower to the south. During the
remainder of the week, the Moon will rise ever more after sundown
as it goes through its waning gibbous phase, passing just south of
Jupiter the morning of Saturday, the 4th and a bit farther to the
south of Saturn the evening of Tuesday the 6th. The Moon will also
pass its closest point to the Earth -- perigee -- on its elliptical
orbit only a day after it passes full. The combination of the
alignment of the Moon with the Sun and the relative lunar closeness
will produce especially high tides in coastal areas.
Mercury first disappeared from the morning sky, and now Venus is
gone, as both the inferior planets -- those inside the orbit of the
Earth -- are on the far side of the Sun and too close in angle to
it to be seen. However, the three bright superior planets -- those
outside the terrestrial orbit -- now march in stately fashion
across the nighttime sky. Jupiter is well up in the southeast in
evening twilight. Saturn then climbs the eastern sky by 9 PM or
so. Finally, Mars rises around 3:30 AM and is nicely visible in
the eastern sky at dawn. Earth is slowly catching up to Mars in
orbit, but the process is slow, and it will be some time before the
red planet is visible in the evening. Its rapid motion to the east
against the background stars is now especially fast. Now in Leo,
Mars will pass about a degree north of the first magnitude star
Regulus between the mornings of Monday the 5th and Tuesday the 6th.
The early evening now is a stage for the great Summer Triangle of
stars, great Deneb overhead, Vega a bit to the west and Altair to
the south of them. Look too for the lonely bright star Fomalhaut
gliding slowly not far above the southern horizon, the luminary of
Piscis Austrinus, the "Southern Fish. Below it is the lovely
"modern" constellation Grus, the Crane. If you have no southern
obscuration, Grus for all the world looks like a great bird
stalking on spindly legs across the southern horizon.
