Discovered by Lacaille in 1751-52.
This cluster was one of the finest open clusters discovered by Abbe Lacaille when he was in South Africa during 1751-1752.
This cluster is one of the youngest known, with an estimated age of only 7.1 million years (Sky Catalog 2000). Its hottest star is of spectral type B0. According to Burnham, the 3 brightest stars are blue giants of mag 5.75 and spectral type B9, mag 5.94 and type B3, and mag 6.80/B2, while the fourth brightest star is a mag 7.58 M2 red supergiant. Another mag 5.7/spectral type A1 star is probably also a member, another white supergiant: This star would be the brioghtest of the cluster at about absolute magnitude -7.7 (83,000 solar luminosities).
Situated close to the cluster is a huge dark area of the sky, right within the band of the Milky Way: the Coal Sack. This is a huge dark nebula, probably the nearest at 500 to 600 light years distance, and 60 to 70 light years diameter.
Hello TrevorW:
Very pretty image.
Unattainable for my, by my latitude, although a long time ago I saw through a telescope, in a hotel in Acapulco, that is much more to the south of my residence.
Many greetings
Cesar
Nice image Trevor. Stars look nice. Just keep an eye on the histogram you appear to have clipped this image severely, wheather to get the background black or just by accident you have probably lost quite a bit in the faint areas of the starfield.
For anyone interested, the brightest stars in the cluster form a capital A (inverted in the image). The brightest star is the variable star NSV 6008 at the apex of the A. Wikipedia-Jewel Box (star cluster)-incorrectly identifies the (orange) red star as kappa Crucis. It is actually the variable star DU Crucis.
Kappa Crucis is actually at the bottom of the right leg of the A.
