according to the Arabs, is a constellation
associated with the rainy season of the ancient middle east. Persian,
Syrian and Turkish languages call it the Water Bucket. The Egyptians
associated these stars with Khnum, their god of water, who caused
the Nile to overflow when he dipped his water bucket into the
river. Remember the importance of the overflowing Nile as it brought
nutrients and fertility to the crops. The Egyptian heiroglyph
for water is the same as the sign used by astrologers for Aquarius,
a pair of wavy lines suggesting the surface of a river. At times
the constellation has been depicted as an ass carrying two water
lugs on its back.
The Greeks held to this same idea, but named the constellation
for Ganymede, the Trojan boy carried off to Mount Olympus to serve
as cup-bearer to the gods.
Aquarius is the first sign of the zodiac in India, where its patron
saint is Varuna. This ancient god was originally the all-powerful
lord of all the heavens and creator of the stars. But later he
was looked on as just god of the water who looked down on the
Earth through the thousand eyes of the stars. From his throat
issued the seven streams of heaven. Varuna patrols his realm on
a fabulous steed, half crocodile and half bird. So he is quite
able to patrol both the air and the sea.
The stars of Aquarius lie between those of Pisces and Capricornus
along the ecliptic. To the north is the Great Square of Pegasus,
and to the south is the first-magnitude star Fomalhaut. Thus it
is an important star group, although it has only a few important
stars. Its alpha star, Sadalmelik, is only at magnitude 3.2, and
there are only about 20 other stars brighter than fifth magnitude.
However, some of these stars form asterisms, star patterns such
as the Water Jar, a trefoil (resembling the Mercedes-Benz symbol)
of Pi, Gamma, and Eta-Aquarii surrounding Zeta. This Y-shaped
group lies to the east of Sadalmelik. Zeta-Aquarii is one of a
number of interesting double stars. It is a beautiful pair of
fourth-magnitude stars separated by about 3 arcseconds. The colors
of the pair are given as pale green and pale yellow. Another star
of note is R-Aquarii, a Mira-type variable star which, over the
space of a year, changes from a dim magnitude 11 to a magnitude
of six.
There are three Messier objects in Aquarius, including M2 and
M72, both globular clusters. M2 is one of the better clusters
and one which can be visible to a keen-eyed observer on a really
dark night. In a small telescope it becomes a ball of faint stars
of magnitude 13. M73 is a rather unusual object among those listed
by Messier. It is only a small group of stars of similar magnitude
that are possibly associated as a multiple-star system. It is
also referred to as NGC 6994. First observed in October 1780,
M73 was described by Messier as “three or four small stars
which look like a nebula at first sight” and contain “a
little nebulosity.” Yet no photograph of M73 has ever revealed
nebulosity around these stars. The four stars form the shape of
a Y, and their magnitudes range from 10.5 to 12.0.
Two planetary nebulae take preeminence in a long list of other
deep-sky objects in Aquarius. The Saturn Nebula, when seen through
a telescope, is a small blue-green dot that Lord Rosse thought
looked like a ringed planet.
The other, the Helix Nebula, NGC 7293, is the closest planetary
nebula to us and occupies an area about half the diameter of the
full Moon. This marvelous deep-sky object can be seen in binoculars
from dark skies. A cloud of gas and dust ejected from a central
star, it resembles a dim smoke ring. Planetary nebulae were named
by Sir William Herschel in 1785 because in telescope views they
may resemble planets. About a thousand of these shells of stars
in their final stages of evolution from giants to dwarfs are known.
The central stars are usually blue in color with temperatures
up to 400,000K.
The planet Neptune was discovered among the stars of Aquarius
154 years ago, in 1846, after its presence had been predicted
and calculated from irregularities in the orbit of Uranus. Aquarius
is also the radiant location for several meteor showers, including
the Eta Aquarids of May, the North Delta Aquarids which peak on
July 29, the South Delta Aquarids which peak on August 13, and
the lesser Iota Aquarids, also of August.
