β Crucis


Beta Crucis, at a visual magnitude of 1.3, is nearly as bright as alpha. It forms the eastern tip of the cross.

With beta Crucis at the top of your glasses you can see much of the Coal Sack: binoculars.
    Dark nebulae such as The Coal Sack are vast regions of interstellar gases and dust thick enough to block out any starlight from penetrating. The Coal Sack is even more dramatic as it is found in the centre of the Milky Way.

One degree southeast of beta is the remarkable Jewel Box star cluster, one of the finest in all the heavens.

The Jewel Box (NGC 4755) is the Southern Hemisphere's equivalent of the Pleiades; a tight group of about a hundred stars. The cluster is quite young, only 14 million years old.

Just visible with the naked eye and a fine sight in binoculars, while small telescopes reveal fifty or so multi-coloured stars (mostly reds and blues). The brightest member is kappa Crucis, and its distance of 7500 light years gives us a good idea of the distance of the cluster in general.

The contrast between the Jewel Box and the Coal Sack, immediately to the south, is striking.

Iota Crucis (h4547), about a degree southwest of the Jewel Box, has a faint but wide companion: 4.7, 10.2; 3, 30.5".

The double star h4524 is found inside an open cluster (NGC 4439, apparent visual magnitude 8.4), a degree east of epsilon Crucis. The double is a good test for binoculars: 8.1, 9.9; 338, 31.3".


Finally, half a field to the north and you have beta, gamma, and mu Crucis: binoculars. Three splendid binocular doubles are found here.

Gamma Crucis is a multiple system (DUN 124AB-F) with a binocular companion; AB: 1.8, 6.5; 26, 128.9".

Mu1 and Mu2 Crucis (DUN 126) form an easy double: 3.9, 4.9; 24, 36.6".

Between gamma and mu is the binocular double h4548: 4.6, 8.9; 166, 51.7".

All files associated with The Constellations Web Page are
1998-2014 by Richard Dibon-Smith.