SKYLIGHTS
Astronomy news for the week starting Friday, December 24, 1999.
The end of the year is now in sight, just one week to go to the
year 2000. A Happy Holiday Season to all. As if in response to
its earlier exciting events, 1999 celebrates its ending quietly,
with little happening except for the steady, dependable flow of the
perpetual stars and planets. After our bright high full Moon of
last week, the Moon descends through its waning gibbous phase,
reaching third quarter on Wednesday, December 29. With the Sun
just past the solstice, the third quarter will have moved just
beyond the autumnal equinox in Virgo, up and to the right if the
first magnitude star Spica and just above the distorted box that
makes the starry figure of Corvus the Crow.
Over the past few months, Jupiter has been pulling to the west of
Saturn, but with the giant planet now moving easterly again, it
will quickly begin to close the gap between the two, as they
prepare for their "grand conjunction" next May 31, an event that
takes place only once every 20 years. In the early evening Mars
can still be seen low in the southwest, while its opposite, Venus,
still dominates the morning sky.
Now, however, in the long dark nights of midwinter, is the time to
contemplate the grandest of all constellations, great Orion, which
rides the sky high to the south before midnight, the mythical
hunter outlined by seven bright stars and looking for all the world
like what he is supposed to be. Located just off, and to the right
of, the faint winter Milky Way, Orion is filled with celestial
sights that include the Orion Nebula, which surrounds the central
star of his "sword." The Orion Nebula, easily visible in the
smallest of binoculars, is a marker for a huge background dark
interstellar cloud of gas and dust that literally fills the
constellation and in which star formation is furiously taking
place, the nebula lit by a set of four recently-made hot young
stars. Orion also contains two of the sky's three first magnitude
supergiants: reddish Betelgeuse, which marks the hunter's right
shoulder, and bluish Rigel, which indicates a right foot that is
commonly depicted as planted on the star Cursa, which begins the
westerly, then southerly, flow of Eridanus, the River. By far the
most notable part of Orion, however, must be his three-star belt,
which falls nearly atop the celestial equator, the Hunter half in
the sky's northern hemisphere, half in the southern.
