In this article, we’ll be sharing with you everything you need to know about the constellation of Caelum, including how to find it, deep space objects contained within it and how to use it to find other night sky objects more easily.
The Constellation of Caelum
Caelum, pronounced seelem, is one of the 14 southern hemisphere constellations that French astronomer Nicolas-Louis de Lacaille (1713-1762) created. Lacaille depicted this constellation as ‘les Burins’ (a pair of sharp engraving tools connected by a ribbon) in his posthumously published Coelum Australe Stelliferum (1763).
The Latin translation of ‘les Burins’ is ‘Caela Sculptoris’ (‘the sculptor’s chisel’) and this was later shortened to ‘Caelum’ (‘chisel’). There are no myths associated with this modern constellation.
To help you spot Caelum, here’s what SkySafari 6 shows.
Caelum has an area of 125 square degrees making it the 81st largest of the 88 recognized constellations. Caelum is located in a relatively empty part of the sky and, as you can tell, has only seven other constellations taking up less space in the heavens.
In the next section discover how to find Caelum.
How To Find Caelum In The Night Sky
Caelum is part of the Lacaille family of constellations and is visible to observers at latitudes between +40° and -90°. This constellation is visible to equatorial and Southern Hemisphere observers. Northern Hemisphere observers south of the 40th parallel can see it along the southern horizon in the late fall and early winter. Southern Hemisphere observers can see it high overhead in January and February.
The constellation of Caelum is bordered by the constellations Columba, Dorado, Eridanus, Horologium, Lepus and Pictor.
To find Caelum, do a naked-eye search for Achernar (Alpha Eri). Hop ~21° north-northeast to Theta Eri, ~14° east to Alpha and Delta Hor (which are ~40 arcminutes apart), then ~4° east to Alpha Caeli.
Alternatively, do a naked-eye search for Canopus (Alpha Car). Hop ~17° north to Beta Col, then ~14° to Alpha Caeli. Alpha Caeli is ~20° northwest of Canopus. You can measure these distances with your hand at arm’s length.
To find Caelum’s exact position for your location on any night, use software such as Stellarium (free) or SkySafari.
Caelum’s Brightest Stars
Being such a small constellation, it shouldn’t be a surprise to learn that Caelum contains very few significant stars. In fact, there are just four that shine at magnitude five or brighter. The brightest, Alpha Caeli, only shines at magnitude 4.4.
All of these stars are shown in the star chart below, with their data shared below that.
Alpha Caeli – This variable double star is the brightest in Caelum and is 66 light-years away. The magnitude 4.44 yellow-white, main-sequence primary has a magnitude 12.50 dwarf secondary 7.5 arcseconds away.
Beta Caeli – This magnitude 5.03 yellow-white, main-sequence star is the third brightest star in Caelum and is 94 light-years away. Its mass is 1.5 Solar masses, its diameter is 1.7 Solar diameters and it’s 1.2 times hotter than the Sun.
Gamma1 Caeli – This double star is the second brightest star in Caelum and is 181 light-years away. The magnitude 4.57 orange giant primary and its magnitude 8.17 secondary component are 3.2 arcseconds apart.
Delta Caeli – This magnitude 5.07 blue subgiant is the fourth brightest star in Caelum. This eruptive variable is 704 light-years away.
Star Hopping From Caelum
Caelum is too small and dim to be a good starting point for star hopping.
Objects To See Within Caelum
Caelum doesn’t contain any Messier objects or other deep sky objects suitable for small telescope users.
Caelum, one of the smallest and dimmest constellations, contains very few notable stars and no deep sky objects for small telescope users. Look for it between Eridanus and Carina if you’re observing from equatorial or southern latitudes.