Capricornus
Capricornus, the "sea-goat" with the upper body of a goat and the lower body of a fish. The smallest constellation of the zodiac, it carries the tale of the god Pan and his transformation.
Science
The scienceCapricornus is the smallest in area of all the zodiac constellations and its stars are faint, so the trick is to first find the outline of a large triangle, or a smiling mouth. The chief star Deneb Algedi (meaning "the tail of the goat") is in fact a nearby star just 39 light-years away. It holds a special place in the history of astronomy: long ago the "winter solstice," where the Sun sinks farthest south during the year, lay in this constellation, and its line of latitude is still called the "Tropic of Capricorn." Here too, in 1846, the planet Neptune was discovered right where prediction placed it, in the direction of Capricornus.
Mythology
How it became a constellationCapricornus is said to depict the god Pan. When the monster Typhon attacked as the gods feasted by the Nile, Pan tried to escape by turning into a fish and leaping into the river. But in his haste the transformation came out only half finished, so that only his submerged lower half became a fish's tail while his upper half stayed a goat — the comical form of the "sea-goat." Zeus, delighted by the witty escape and the ludicrous shape, raised Pan into the sky as a constellation.
Observing Guide
how to observe🔭 How to find it
Between late summer and autumn, look down and to the southeast from Altair (in Aquila), and you'll find Capricornus — a large triangle, or smiling-mouth outline, with no bright stars. Trace a wide triangle using its three vertices: Algedi and Dabih at the western end, and the tail star Deneb Algedi to the east. As the smallest and faintest of the twelve zodiac constellations, it's easier to find under a dark sky.
✨ What to look for
Capricornus's standout sight is the globular cluster M30, in the south of the constellation. It's a core-collapse globular with an extremely dense center, appearing in a small telescope as a round smudge with a bright core, while larger apertures resolve its outer stars. Aside from this, notable bright objects are scarce, so M30 is essentially the only major target.
📍 Where to see it (US · Canada · UK · Australia)
With declinations of −12° to −27°, Capricornus sits south of the equator. From the US and southern Canada it rises fairly low in the south on late-summer-to-autumn nights (August–October), and lower still from the UK, so a dark site with a clear southern horizon is best. From Australia the Sea-Goat rides high overhead during the southern winter, its dim outline much easier to make out than from the north.