Leo, the Lion
Some say that a strange
mythological creature, half human and half animal, once represented
the summer Sun. Summer was to the Egyptians the most important
of the seasons, for the rising of the Nile led to the life-giving
floods that in turn led to the promise of bountiful harvests.
These people gave over their thoughts to the coming of the season,
and their symbolism carried into their astronomy. At this time
of year lions from the outlying deserts came down to the Nile
Valley to seek relief from the heat. Lions, then, were associated
with the coming of summer when the Sun was approaching the constellation
we know as Leo. In mid-summer the Sun passed from the stars of
Leo and into those of Virgo, the Virgin, representative of the
harvest. These two star groups seemed to be in control of the
Sun during the most crucial time of the year. And so, as the two
signs of summer met, a creature with the body of a lion and the
head of a woman was born—the Sphinx.
The stars of Leo were
those of a lion to many of the civilizations of ancient times.
Not only for the Near East and for the Greeks (whose Leo was the
lion who fell from heaven as a meteor, landing in Corinth where
he ravaged the land until he was slain by Hercules), but even
in the West. These stars were thought to be a puma about to pounce
on its prey, according to Peruvian legend. In the middle ages
some Christians used this heavenly lion to relate the story of
Daniel.
The principal star in
the constellation is Regulus, the heart of the lion, or Cor Leonis.
This was the first of the four Royal Stars of ancient Persia,
with Antares, Fomalhaut and Aldebaran. These stars are separated
by about six hours in right ascension, and so they well marked
the four quarters of the sky. Regulus is a first magnitude star,
although it is surpassed in brightness by 20 other stars. It lies
almost exactly on the plane of the ecliptic, so that once a year,
on about August 23, it is eclipsed by the Sun. Infrequently it
is occulted by the Moon.
Leo serves as the radiant
of an important meteor shower, the November Leonids, which are
associated with Comet Tempel-Tuttle. The great Leonid shower of
1966 is remembered as having a rate of visible infall in excess
of 2000 per minute over a period of a half-hour. There is every
reason to expect a particularly strong display from this stream
in the year 1999.
There
are five Messier objects in Leo, as well as a number of other
galaxies and a variety of multiple stars, including doubles Regulus
and Algieba (Gamma Leonis). A galaxy hop and a review of double
stars are published in separate articles in the April 1997 issue
of Sky & Telescope.
Conrad Jung's photo
includes a triangle with galaxy NGC 3628 north of M66 (left) and
M65. Each shines with a magnitude of about 9½, and all
three are about 30 million light-years away.