Constellation

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Constellations Ursa Major (the "Big Dipper") and Ursa Minor (the "Little Dipper") with Polaris, the North Star. Children around the Northern hemisphere are taught to find the North Star (which hangs over the North Pole) by means of these two easy-to-spot constellations. The Big Dipper's outer lip points to the North Star, which is at the end of the handle of the Little Dipper. In the course of one night, only the North Star appears unmoving, while all the other stars appear to revolve part-way around it. The other stars revolve all the way around the North Star in approximately one 24-hour day (one rotation of the earth).

A constellation is an officially recognised formation of stars as viewed in the sky from the earth. Ancient astronomers perceived figures, often men or animals, in the night sky, thus ordering its apparent chaos. Such figures were arbitrarily chosen; thus, numerous ancient constellations were independently imagined by different cultures, including those of China and India. The 88 modern constellations which comprise the entire sky, however, derive from civilisations further west. Their boundaries were defined by the International Astronomical Union in 1925. The majority of them are ancient constellations, and have names often associated with Greek mythology while others, mainly situated south of the celestial equator, were introduced in the age of exploration by European explorers and are named after scientific instruments or newly found animal species.

A Greek letter followed by the Latin genitive (possessive) case of a constellation name is conventionally used to designate the brighter stars in a group. For example, the fifth-brightest star in the constellation Eridanus is given a name consisting of the fifth letter of the Greek alphabet and the name of the constellation: "epsilon Eridani", meaning "fifth (star) of Eridanus". The order of brightness is not strictly adhered to, however; for example, β Orionis (Rigel) is brighter than α Orionis (Betelgeuse).

History of the Western constellations[edit]

Most constellations have their origins in the ancient Greek, Egyptian and Babylonian cultures. They are mentioned in the Book of Job, as in this apostrophe:^[1]

In the third century BC, Aratos of Soli composed Phainomena, a didactic poem about the mythology of the constellations, which was the basis of the catalog of 48 constellations by the Greek astronomer Ptolemy:

• the 12 constellations of the Zodiac: Aries, Taurus, Gemini, Cancer, Leo, Virgo, Libra, Scorpius, Sagittarius, Capricornus, Aquarius and Pisces
• 21 northern constellations: Ursa Major, Ursa Minor, Draco, Cepheus, Bootes, Corona Septentrionalis, Hercules, Lyra, Cygnus, Cassiopea, Perseus, Andromeda, Triangulum, Auriga, Pegasus, Equuleus, Delphinus, Sagitta, Aquila, Ophiuchus and Serpens
• 15 southern constellations: Cetus, Eridanus, Lepus, Orion, Canis Major, Canis Minor, Argo, Hydra, Crater, Corvus, Centaurus, Lupus, Ara, Corona Meridionalis and Piscis Australis.

At the end of the 16th century, the Dutch sailors Pieter Dirckszoon Keyser and Frederick de Houtman suggested twelve new constellations: Apis, Apus Indica, Chamaeleon, Dorado, Grus, Hydrus, Indus, Pavo, Phoenix, Triangulum Australe, Tucana and Piscis Volans. In 1603 these were added by Johann Beyer to his important atlas Uranometria, as well as Coma Berenices.

The Gdansk astronomer Johann Hevelius added 10 further constellations in his maps, published in 1690 (Firmamentum Sobiescianum and Prodomus Astronomiæ): Canes Venatici, Lacerta, Leo minor, Lynx, Uraniæ Sextans, Scutum Sobiescianum, Triangulum Minus, Vulpecula & Anser, Cerberus and Mons Mænalus.

In 1751, the French astronomer abbot Nicolas Louis de Lacaille went to the Cape of Good Hope for the purpose of determining the sun's parallax by observations of the parallaxes of Mars and Venus, and incidentally to make observations on the other southern hemisphere stars. In 1763, Lacaille published the results of this successful undertaking, the observations of ten thousands stars, in his Coelum australe stelligerum. This work introduced 14 new constellations that were named after scientific instruments and artist's tools:

1. L'atelier du sculpteur, Apparatus Sculptoris (Sculptor)
2. Le fourneau chymique, Fornax Chemica (Fornax)
3. L'horloge (Horologium)
4. Le réticule romboïde, Reticulum Rhomboidalis (Reticulum)
5. Le burin du graveur, Cæla Sculptoris (Caelum)
6. Le chevalet du peintre, Equuleus Pictoris (Pictor)
7. La boussole, Pyxis Nautica (Pyxis)
8. La machine pneumatique, Antlia Pneumatica (Antlia)
9. L'octans (Octans)
10. Le compas (Circinus)
11. L'équerre & la règle, Norma et Regula (Norma)
12. Le télescope (Telescopium)
13. Le microscope (Microscopium)
14. La montagne de la table, Mons Mensae (Mensa)

List of the 88 modern constellations[edit]

Note that Serpens is in two non-contiguous portions but is counted as a single constellation.

References[edit]