SKYLIGHTS
Astronomy news for the week starting Friday, November 20, 1998.
The Moon waxes through its crescent phase this week, reaching first
quarter the night of Thursday, the 26th, about 6 PM when it stands
high to the south near the celestial meridian, exactly 90 degrees
to the east of the Sun and a bit to the west of brilliant Jupiter,
which, except for the Moon, dominates the evening skies.
The Leonid shower is now over, a nice but not spectacular display
seen in North America. There is still a possibility of seeing a
Leonid display next year as we pass the orbit of Comet Temple-
Tuttle on November 17. However, Jupiter's gravity is expected to
shift the location of the meteoroid stream such that we will not
see it in 2029, when it would again be expected. The next
significant shower will be the Geminids, which run from December 6
to December 19, peaking on December 13 and 14. This fine shower,
while nothing like the Leonids at their peak, typically produces
over one per minute and is associated with an object called 3200
Phaeton. Once thought to be an asteroid, Phaeton seems now clearly
to be a defunct comet. The number of annual meteor showers is
greatly underappreciated, over 110 recognized. Many, however,
produce only a few meteors per night and require dedicated
observation. Others occur only in daylight and can be observed
only by radar, the radio signals bouncing off the ionization trails
made by the heated meteoroids as they slam through the
atmosphere.
The winter constellations are now climbing the eastern sky in late
evening, Orion nicely up by 10 PM, his bright three-star belt
riding the celestial equator, reddish Betelgeuse to the upper left
of it, Rigel to the lower right. Look too for Capella climbing the
northeastern sky. The sixth brightest star as seen from Earth,
Capella is the first magnitude star closest to the north celestial
pole, marked by Polaris. The closest of first magnitude to the
south celestial pole is Alpha Centauri, coincidentally the closest
star to the Earth, unfortunately invisible from latitudes above 30
degrees north. Capella is the luminary of the constellation
Auriga, the Charioteer, made by a rough pentagon of stars. On a
dark night you can see the Milky Way pass dimly through the
southern part of the constellation, the celestial stream filled
with clusters and dark clouds that are spawning stars.
