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NGC4755
NGC4755 - Jewel Box to Mimosa
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The Jewel Box (also known as NGC
4755 or Kappa Crucis Cluster) is an open cluster
in the Crux constellation. As Kappa Crucis, it has
a Bayer designation despite the fact that it is a
cluster rather than an individual star.
It was one of the finest open
clusters discovered by Nicolas Louis de 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. It has an
apparent magnitude of 4.2, and is located 6,440
light years from Earth and contains around 100
stars.
This famous group of young
bright stars was named the Jewel Box from its
description by Sir John Herschel as 'a casket of
variously coloured precious stones', which refers
to its appearance in the telescope. The bright
orange star is Kappa Crucis, and it contrasts
strongly against its predominantly blue, hot
companions. Kappa Crucis is a very large, (hence
very luminous) quite young star in its red
supergiant stage, which paradoxically indicates
that its life is drawing to a close. The cluster
looks like a star to the unaided eye and appears
close to the eastern-most star of the Southern
Cross (Beta Crucis), so is only visible from
southern latitudes.
(From Wikipedia, the free encyclopaedia)
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Information
 | Instrument: William Optics FLT132 |
| Exposure: 3 x 1 min for each LRGB |
| Camera: SBIG STL11Km |
| Date: 24/12/08 |
| Exposure start: 3:30 |
| Location: Thorpdale, Vic |
| Autoguider: William Optics Megrez88FD + Meade DSI2
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| Enhancement: CCD Soft, Adobe Photoshop CS3, |
Notes: Fighting a lot of dew on the guide scope, tracking
was 9.5/10 |
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