SKYLIGHTS
Astronomy news for the week starting Sunday, May 7, 2000.
Find stars that have orbiting planets! The "Planet Project" has
been added to the Stars Website.
The next Skylights will appear on Saturday, May 13. The Moon,
after leaving the great gathering of planets last week, waxes to
first quarter early in the week, the phase reached on Wednesday,
May 10, just before passing the Sickle of Leo, the bright star
Regulus seen down and to the left.
While the Moon leaves their vicinity, the Gang of Ancient Planets
(made of Mercury, Venus, Mars, Jupiter, and Saturn) continues to
group closer in the neighborhood of the Sun (which makes the
gathering invisible). As part of the assembly, we have a week of
conjunctions. Jupiter first passes the Sun on Sunday, May 7, far
to the solar back, six astronomical units (900 million kilometers,
550 million miles) away. Saturn, 70 percent more distant, follows
on Wednesday, the 10th. In between, Mercury passes superior
conjunction with the Sun, when it is in back of the Sun as well, on
Monday, the 8th. Afterward, among the Ancients, only Venus is left
to the west of the Sun. (Its turn for conjunction does not come
until June 11.) The grouping, while fascinating as an invisible
geometric display, has no physical consequences whatsoever. Over
the ages such things have happened countless times. The obvious
closeness of Jupiter and Saturn is a prelude for their Grand
Conjunction on May 31.
While the three outer planets (Uranus, Neptune, and Pluto) are
excluded from the Great Gathering, at least one raises its hand, as
Neptune begins its retrograde, or backward, motion against the
background of Capricornus, as it prepares for its opposition with
the Sun next July.
In late evening, around 11 PM, the Big Dipper, at the top of a
stack of wonderful constellations, crosses nearly overhead for
those in the mid-northern hemisphere. Descending southward, we
pass the modern constellation Canes Venatici (the Hunting Dogs) and
then the lacy cluster than makes Coma Berenices (Berenices Hair).
Farther down, sprawled across the celestial equator, is Virgo, with
bright Spica, up and to the left of Corvus (the Crow). Crossing
the tail of Hydra (the Water Serpent), we enter the realm of
Centaurus (the Centaur), with its great globular cluster Omega
Centauri (seen well only south of about 35 degrees north latitude).
Finally, to the south of Centaurus (and west of Alpha Centauri, the
closest star to the Earth), lies magnificent Crux, the Southern
Cross, which for those in mid-southern latitudes crosses the sky
much as the Dipper does for those in the north. Between the Dipper
and the North Celestial Pole whips the tail of Draco, the Dragon,
and between Crux and the South Pole buzzes Musca, the Fly.
