ABOUT THIS IMAGE: 

The combination of images taken by three exceptional telescopes, the ESO Very Large Telescope on Cerro Paranal , the MPG/ESO 2.2-meter telescope at ESO's La Silla observatory and the NASA/ESA Hubble Space Telescope, has allowed the stunning Jewel Box star cluster to be seen in a whole new light.

Star clusters are among the most visually alluring and astrophysically fascinating objects in the sky. One of the most spectacular nestles deep in the southern skies near the Southern Cross in the constellation of Crux.

The Kappa Crucis Cluster, also known as NGC 4755 or simply the "Jewel Box" is just bright enough to be seen with the unaided eye. It was given its nickname by the English astronomer John Herschel in the 1830s because the striking color contrasts of its pale blue and orange stars seen through a telescope reminded Herschel of a piece of exotic jewelry.

Open clusters [1] such as NGC 4755 typically contain anything from a few to thousands of stars that are loosely bound together by gravity. Because the stars all formed together from the same cloud of gas and dust their ages and chemical makeup are similar, which makes them ideal laboratories for studying how stars evolve.

The position of the cluster amongst the rich star fields and dust clouds of the southern Milky Way is shown in the very wide field view generated from the Digitized Sky Survey 2 data. (see s0940beo) This image also includes one of the stars of the Southern Cross as well as part of the huge dark cloud of the Coal Sack [2].

A new image taken with the Wide Field Imager (WFI) on the MPG/ESO 2.2-meter telescope at ESO's La Silla Observatory in Chile shows the cluster and its rich surroundings in all their multicolored glory. The large field of view of the WFI shows a vast number of stars. Many are located behind the dusty clouds of the Milky Way and therefore appear red [3].

The FORS1 instrument on the ESO Very Large Telescope (VLT) allows a much closer look at the cluster itself. The telescope's huge mirror and exquisite image quality have resulted in a brand-new, very sharp view despite a total exposure time of just 5 seconds. This new image is one of the best ever taken of this cluster from the ground.

The Jewel Box cluster is about 6400 light-years away and is approximately 16 million years old.

Notes:

[1] Open, or galactic, star clusters are not to be confused with globular clusters ? huge balls of tens of thousands of ancient stars in orbit around our galaxy and others. It seems that most stars, including our Sun, formed in open clusters.

[2] The Coal Sack is a dark nebula in the Southern Hemisphere, near the Southern Cross, that can be seen with the unaided eye. A dark nebula is not the complete absence of light, but an interstellar cloud of thick dust that obscures most background light in the visible.

[3] If the light from a distant star passes through dust clouds in space the blue light is scattered and absorbed more than the red. As a result the starlight looks redder when it arrives on Earth. The same effect creates the glorious red colors of terrestrial sunsets.