The traditional constellations of autumn, now occupying the southern part of the evening sky this first full month of fall, have a rich body of lore and mythology associated with them, even though their stars are rather average in brightness.
Several of these constellations are dwelling in the celestial “sea;” that is, they are of a “watery” nature. These include Capricornus, the Sea Goat; Aquarius, the Water Carrier; Pisces, the Fishes; Piscis Austrinus, the Southern Fish; Cetus, the Sea Monster; and Eridanus, the River. The first three constellations belong in the zodiac, and all members of this group have been associated with the rainy season of ancient Mideast lands. There is also a mythological connection between these star pictures and an ancient great flood in the Tigris-Euphrates basin, which has sometimes been linked to the Deluge written in Genesis.
Aquarius, the Water Carrier
Among the “watery” constellations is the Man with the Water Jar, Aquarius, which is still in a commanding location in the south-southwest sky. The rich mythology of the Water Carrier is very ancient, tracing back to the earliest civilizations in the Tigris and Euphrates valleys.
In fact, on some cylinder seals depicted these rivers as pouring out from Aquarius’ water jar. The ancient Egyptians had an equally picturesque image of this constellation that they associated with the Nile’s annual flooding, which, far from being disastrous, added a new layer each year to the valley’s fertile soil. The Egyptians believed the flooding was caused by Aquarius dipping his water jar into the river to refill it.
Grus, the Crane
Grus, the Crane is also among these watery constellations, for this wading bird often inhabits swampy and marshy terrain. With its two 2nd-magnitude stars marking the bottom of a distinctive inverted Y-shaped pattern, with 3rd magnitude Gamma at the top, Grus is actually a prominent fall constellation for viewers in the tropics and the Southern Hemisphere.
Directly above Grus is Piscis Austrinus, which has the only 1st-magnitude star, Fomalhaut, in the whole collection of watery constellations. Indeed, Fomalhaut is the only “true” 1st-magnitude star of autumn. Though Vega, Deneb, and Altair are still very much present high in the west, they form the Summer Triangle. Fomalhaut is a white star, only about twice as large as the Sun and some 14 times as bright. It appears prominent to us because it is only 25 light-years away. So the light you see coming from Fomalhaut tonight actually started on its journey to Earth back in 1991.