This, too, is an ancient constellation, as it would appear from stone fragments of Babylonian times representing a capricorn shaped like a goat in the trunk, while the back looks like a fish tail.
This weird conformation can be explained by the fact that at the time, the Sun entered the constellation to coincide with the Winter Solstice, i.e., when its maximum negative was below the celestial equator. Therefore the constellation front was seen as a goat climbing to the top, while the back suggested the idea of a fish dipping into the mysterious Southern Ocean.
The myth behind the representation is connected to the birth of Zeus, son of Chronus. The latter had been predicted that he would be dethroned by one of his sons, just as he had killed his own father. Therefore Chronus, to foil the prophecy, began to swallow his children as his wife Rhea gave birth to them. At the birth of Zeus, Rhea - to save her last offspring - at the moment of presenting him to his father, replaced him with a rock wrapped in thick bandages, which Chronus swallowed hastily.
The child, instead, was entrusted to two nymphs, who hid him in a cave in Crete, and had him breast-fed by the goat Amalthea. According to another version of the myth, Amalthea was the name of the nymph, daughter of Oceanus and Tethys, who took care of the baby Zeus, feeding him milk from a goat, whose hideous appearance had induced the gods to shut it up inside the cave.
When the goat died, perhaps killed by Zeus himself, he put on her skin, which made him invulnerable, overthrew Chronus and immortalized his nurse in the constellation of Capricorn.
Like Cancer, Capricorn too is an inconspicuous constellation: the few stars visible with the naked-eye cover an area of 414 sq. degrees. It culminates around midnight for about a month, from mid-July to mid August, lying low on the horizon at our latitude. It borders the Aquarium in the north-east, the Southern Fish and the Microscope in the south, the Archer and the Eagle in the west.
Because two thousand years ago the winter solstice was in the Capricorn, the latitude at which the Sun culminated was called "Tropic of Capricorn" and this name has been preserved by tradition, although the solstice has now moved to the Sagittarius.