ABOUT THIS IMAGE:

This image is a "close-up" view from the NASA/ESA Hubble Space Telescope of NGC 4755, or the Jewel Box cluster. Several very bright, pale blue supergiant stars, a solitary ruby-red supergiant and a variety of other brilliantly colored stars are visible in the image, as well as many much fainter ones, often with intriguing colors. The huge variety in brightness exists because the brighter stars are 15 to 20 times the mass of the Sun, while the dim points are less than half the mass of the Sun. More massive stars shine much more brilliantly. They also age faster and make the transition to giant stars much more quickly than their faint, less-massive siblings.

The Jewel Box cluster is regarded as one of the finest objects in the southern sky. It is visible with the naked eye with a visual magnitude of 4.2. The Jewel Box cluster is impressive when viewed with binoculars or a small or large telescope. 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 The three brightest members of the cluster lie in a straight line and are known as the 'traffic lights' due to their varying colors.

The Jewel Box may be visually colorful in images taken on Earth, but observing from space allows the NASA/ESA Hubble Space Telescope to capture light of shorter wavelengths than can not be seen by telescopes on the ground. This new Hubble image of the core of the cluster represents the first comprehensive far ultraviolet to near-infrared image of an open galactic cluster. It was created from images taken through seven filters, allowing viewers to see details never seen before. It was taken near the end of the long life of the Wide Field Planetary Camera 2 ? Hubble's workhorse camera up until the recent Servicing Mission, when it was removed and brought back to Earth. Several very bright, pale blue supergiant stars, a solitary ruby-red supergiant and a variety of other brilliantly colored stars are visible in the Hubble image, as well as many much fainter ones. The intriguing colors of many of the stars result from their differing intensities at different ultraviolet wavelengths.

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