Located in the southern sky, Caelum is a faint constellation that was a introduced in the 1750s by Nicolas Louis de Lacaille. In Latin, the name means “chisel,” but it was formerly known as Caelum Sculptorium. Caelum Scupltorium is Latin for “the engravers’ chisel.” In Latin, the word caelum means “sky, heaven, atmosphere”. It is the 8th-smallest constellation in the entire nights sky.
Due to its small size and location away from the plane of the Milky Way, Caelum is a rather barren constellation, with few objects of interest. The constellation’s brightest star, Alpha Caeli, is only of magnitude 4.45.
Its main stars are visible in favorable viewing conditions, plus a clear southern horizon for part of the year as far as about the 41st parallel north. This makes the constellation visible in some parts of the southern Pacific Northwest. Covering only 125 square degrees, Caelum ranks 81st of the 88 modern constellations in regards to size.
|Visibility In Pacific Northwest||September to February|
|Best Times To View||January|
|Right Ascension||04h 19.5m to 05h 05.1m|
|Declination||−27.02° to −48.74°|
|Area||125 square degrees|
|Brightest Object||α Cae|
|Neighboring Constellations||Columba, Lepus, Eridanus, Horologium, Dorado, Pictor|
Caelum was created in the 18th century by French astronomer Nicolas Louis de Lacaille, during a period in which he created 14 new constellations. Caelum still retains its name Burin among French speakers, which was Latinized in his catalogue of 1763 as Caelum Sculptoris or “Engraver’s Chisel.”
Francis Baily shortened the name of the constellation to Caelum, which was suggested by John Herschel. In Lacaille’s original chart, it was shown as a pair of engraver’s tools: a standard burin and more specific shape-forming échoppe tied by a ribbon, but came to be ascribed a simple chisel. Johann Elert Bode stated the name as plural with a singular possessor, Caela Scalptoris, but this did not stick.
Caelum is a faint constellation, as there are no stars in the constellation with a magnitude brighter than 4. There are 2 two stars brighter than magnitude 5.
In 1756m Lacaille gave six stars Bayer designations, labeling them Alpha to Zeta, but omitted Epsilon and designated two adjacent stars as Gamma. Bode extended the designations to Rho for other stars, but most of these have fallen out of use. Caelum is too far south for any of its stars to bear Flamsteed designations.
Due to its small size and location away from the plane of the Milky Way, Caelum is rather devoid of deep-sky objects, and contains no Messier objects. The only deep-sky object in Caelum to receive much attention is HE0450-2958, an unusual Seyfert galaxy.
The 13th magnitude planetary nebula PN G243-37.1 is also in the eastern regions of the constellation. It is one of only a few planetary nebulae found in the galactic halo, but it is below the Milky Way disk.