Star Talk: Great Celestial Sea is visible in night sky during late autumn

Stretching from the southwestern part of the autumn evening sky to its southeastern region is the Gr

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Stretching from the southwestern part of the autumn evening sky to its southeastern region is the Great Celestial Sea of star pictures. These are the “water” constellations, a vast expanse of dim stars that all have an association with water in their mythology.

Leading this progression is Capricornus the sea goat, a half-goat and half-fish creature. Legend has it that Capricornus is the partial alteration of the god Pan. One day Pan, who had the form of a goat, was playing his pipes along a riverbank when he was startled by the approach of the monster Typhon. Pan lunged toward the river as he hastily changed himself into a fish but in his “panic,” only his hindquarters became a fish while his front remained unchanged as a goat.

When Pan emerged from the water, he saw that Typhon had paralyzed Jupiter by tearing out his arm and leg muscles. To save Jupiter, Pan made a piercing, shrill noise on his pipes that caused Typhon to flee. Mercury heard the sound and flew in on his winged sandals in time to assist Pan in collecting Jupiter’s muscles. Together, they reassembled the father god.

Now whole again, Jupiter quickly rose to Olympus, gathered his thunderbolts, aimed one at Typhon and struck him. The jolt knocked the beast back into his underground den. In gratitude, Jupiter eternalized Pan as the goat-fish star pattern in the autumn sky. Capricornus appears over the southwest point about 7 p.m. this time of year.

Aquarius appears

To the upper left of Capricornus is Aquarius the water bearer. His stellar outline portrays a man carrying an urn filled with water. In ancient times, water carriers served as waiters at banquets whether on Earth or in the heavens. Aquarius, known as Ganymede in Greek mythology, became the cupbearer to the gods when Jupiter sent an eagle to abduct him. The eagle snatched Ganymede and transported him to Mount Olympus, where he served in the banquet halls of the Olympic gods.

In ancient Egypt, it was believed that the Nile River flooded when Aquarius refilled his great urn by dipping it into the river. The water dripping from the lip of the jug caused the rainy season.

In a version of the Great Flood story, it was Aquarius who poured the water that caused the great torrent of Earth. It was Piscis Austrinus, now the constellation of the southern fish, which saved the world by drinking the floodwaters. The southern fish is always portrayed with its mouth open, catching the water that is pouring from the water carrier’s urn.

Piscis Austrinus is directly below Aquarius. During the last week of November, it can be found skimming low above the south horizon around 6 p.m. Its brightest star is Fomalhaut, a name that means “the fish’s mouth.” Fomalhaut is also known as the Solitary One because it is the only bright star across the celestial “sea.”

The constellation we usually think of as the fishes, Pisces, is on its eastern side of Aquarius. Two fishes are represented in an inconspicuous group of stars that form a large “V.” At the top of each side of the “V” are jagged circles of faint stars that designate each fish. The “V” indicates a ribbon of stars that ties the two fishes together. This stellar ribbon is connected at a star named “Al Rischa,” which translates from the Arabic as “the knot.”

Roman mythology has Pisces as Venus and her son Cupid. Their story is similar to that of Capricornus because it also has the two along a riverbank when the beast Typhon came along. To escape the monster, both Venus and Cupid transformed themselves into fish and swam off to the sea. In order not to be separated from one another, they tied themselves together with a long cord. They successfully escaped and this adventure is commemorated in the stars of Pisces. The two fish are sometimes called Venus and Cupid.

Apparently, Jupiter became so annoyed at Typhon — whose key pastime seems to have been to frighten others — that the father of the gods finally disposed of the monster and Typhon now lies crushed beneath Mount Etna.

Sea monster

Below Pisces and hovering in the southeast around 7 p.m. is Cetus. Usually known as the constellation of the whale, Cetus is more likely based on a large, fanciful sea creature that ancient people had heard about but had never seen. Although the origin of Cetus might ultimately lie with whales, graphic representations of this constellation illustrate it as a fictitious sea monster with a half-dragon, half-fish shape.

In the Perseus-Andromeda story, Cetus was portrayed as a lumbering sea monster, laden with seaweeds, which would have devoured Andromeda had Perseus not shown it the head of Medusa. By 9 p.m., Cetus is passing over the south point; the star Al Rischa lies just above the whale’s midsection.

Finally, the western-most of the “water” stars is Eridanus, the river. This constellation begins with the star Kursa situated just above Rigel, the star that indicates the right foot of Orion. Eridanus winds westward toward Cetus then back toward Orion then goes diagonally westward to the horizon. The star Achernar, at the end of the river, is never visible from our latitude; nevertheless, most of Eridanus is above our southern horizon around 11 p.m.

December Sky

Although the constellations of autumn across the south are low and faint and can be a challenge for the novice stargazer to find, what is not faint in our autumn sky this year are the two planets Venus and Jupiter.

Venus is low in the southwest a half hour after sunset but its radiating brightness makes it an easy target to find if you don’t look too late. As December progresses, this planet will come into view higher in the sky after sunset and will set correspondingly later. Tonight (Nov. 27), the crescent moon will be to the upper left of Venus. A similar setup between the moon and Venus will happen on Dec. 27.

Jupiter’s brilliant light shines to us from the southeast during early evening. This giant planet is almost halfway up the sky by the time dusk ends — about 6 p.m. this time of year. Although the planet dims slightly during December as its distance from us increases, you will be pressed to notice any difference in its brightness. On Dec. 6, the waxing gibbous moon will be to the upper left of Jupiter.

Richard Monda is an astronomer living in the Capital Region.

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