Ara (constellation)


  • Scorpio
  • Square
  • Southern triangle
  • Bird of paradise
  • Peacock
  • Telescope
  • Southern crown

The altar (Latin Ara ) is a constellation of the southern sky.


The altar is a small memorable constellation, which is south of Scorpio in the sky. By the altar, the starry band of the Milky Way pulls, so you will find several open clusters.


The altar is one of the 48 constellations of the ancient Greek astronomy, which have already been described by Ptolemy.

The name altar was set by Eudoxus of Cnidus, a Greek natural philosophers and mathematicians from the 4th century BC.


After Eudoxus represents the constellation, which he originally called the altar of incense, the altar represents the centaur Cheiron on the 've sacrificed a wolf. Cheiron and the wolf were also displaced as constellations in the sky, as a centaur and Wolf.

According to others, it is the built by Hephaestus altar at which the gods swore an alliance against the Titans.

Celestial objects


The constellation contains due to its southern location no stars with Flamsteed identifier.

β Arae, the brightest star in the sanctuary is 600 light years away. He belongs to the spectral class K3 Ib.

μ Arae is a sunlike star in about 50 light years away. He has a somewhat larger mass and luminosity as our sun and is surrounded by several exoplanets.

Double stars

γ Arae is a double star system 187 light-years away. The 3.5 m bright, bluish-white main star has a faint companion with white 10.5 m. The system can be resolved with an average telescope into individual stars.

ν1 Area is a 820 light-years distant triple star. The two different bright main components orbit each other at a close distance all 3.17 days pulls the darker star in front of the lighter over the brightness decreases slightly. Such binaries are called eclipsing binaries. At a distance of 12.3 arcsec, there is another star with a brightness of 9m.

Variable Stars

R Arae is another eclipsing binary Algol type, in which a faint companion star passes every 4.4 days before the main star and covered him. The apparent brightness increases from 5.9 to 6.9 m from.

Messier and NGC objects

NGC 6193 is a bright star cluster contains about 30 stars. The system was discovered in 1828 by James Dunlop.

NGC 6397 is at a distance of 8,000 light-years, one of the closest globular clusters. Even with the naked eye it is seen as a nebulous spot. In a small telescope of 6 cm opening he can already be resolved into individual stars. In a telescope of 10 cm, it offers a spectacular sight, with groups and chains of stars to show. The globular cluster was discovered in 1752 by Nicolas Louis de Lacaille.