Crater (constellation)

Crater is a small constellation in the southern sky. Its name means “cup” in Latin. It looks like a cup and sits behind another constellation called Hydra, which looks like a water snake.

The stars in Crater are not very bright. The two brightest stars, Delta Crateris and Alpha Crateris, are older orange stars. Another star, Beta Crateris, is actually two stars orbiting each other. Scientists have found planets around some stars in this area. There are also interesting objects like galaxies and a distant bright object called a quasar in Crater.

Mythology

In old Babylonian star charts from around 1100 BC, the stars of Crater were sometimes grouped with the stars of the crow, called Corvus. Some believe these stars, along with the water snake Hydra, were linked to ideas about the underworld.

In Greek stories, Crater is told through a myth about a crow that served the god Apollo. The crow was sent to fetch water but stopped to eat figs until they were ripe. When it finally returned with the water in a cup, it blamed a water snake. Apollo saw this and placed the crow, the cup, and the snake in the sky, arranging them so the crow could never drink from the cup. This tells a lesson about not disobeying the gods.

In Chinese astronomy, the stars of Crater are part of the Vermillion Bird of the South. They represent the bird's wings or a heroic bowman. In the Society Islands, Crater was known as a constellation called Moana-'ohu-noa-'ei-ha'a-moe-hara, meaning "vortex-ocean-in-which-to-lose-crime."

Characteristics

The Crater constellation covers an area of the sky and is one of the 88 constellations. It is next to Leo, Virgo, Corvus, Hydra, and Sextans. In 1922, the International Astronomical Union gave it the short name "Crt". The shape of Crater was set in 1930 by Belgian astronomer Eugène Delporte.

In the equatorial coordinate system, Crater’s right ascension runs from 10^h 51^m 14^s to 11^h 56^m 24^s, and its declination ranges from −6.66° to −25.20°. Because it is in the southern celestial hemisphere, anyone living south of 65°N can see the whole constellation.

Features

Stars

Main article: List of stars in Crater

Johann Bayer, a German mapmaker, used Greek letters to name the brightest stars in this group of stars. Another mapmaker named Bode added a few more, but only one of these, called Psi Crateris, is still used today. John Flamsteed named 31 stars in Crater and part of a nearby group of stars called Hydra. Most of these stars are actually in Hydra.

The three brightest stars in Crater—Delta, Alpha, and Gamma Crateris—form a triangle near a brighter star in Hydra called Nu Hydrae. Delta Crateris is the brightest star in Crater. It is an orange star that is about 163 light-years away from us. Alpha Crateris, also an orange star, marks the base of the cup shape and is about 141 light-years away. Beta Crateris is a pair of stars orbiting each other, one being a white star and the other a tiny, dense star called a white dwarf.

Epsilon and Zeta Crateris mark the edge of the cup. Epsilon Crateris is a large, bright star about 366 light-years away. Zeta Crateris is also a pair of stars, with the bigger one shining brightly and the smaller one much dimmer. These stars are about 326 light-years from us.

Some stars in Crater change in brightness and are favorite targets for stargazers. R Crateris is a red star that dims and brightens over many days. TT Crateris is a system of stars where one pulls material from the other, causing bright flashes of light.

There are also interesting star systems like HD 98800, which is a group of four stars with a disk of dust and gas around them, and HD 96167, a star with a planet orbiting it.

Deep-sky objects

Crater 2 is a small galaxy that orbits our Milky Way galaxy, located about 380,000 light-years away. NGC 3511 is a spiral galaxy that looks almost like our own, and NGC 3513 is a barred spiral galaxy. NGC 3981 is another spiral galaxy with unusual arms.

RX J1131 is a very distant object called a quasar, where a giant black hole is at the center.

Meteor showers

The Eta Craterids is a meteor shower that happens between January 11 and 22, with the most meteors seen around January 16 and 17, near the star Eta Crateris.