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About this Image |
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The great variety of star colors in this open cluster NGC 4755, situated less than 1 degree to the
south-east of the brigth star beta crucis underlies it's name: The Jewel Box.
One of the bright central stars is a red supergiant, in contrast to the many blue stars that surround it.
The cluster, also known as Kappa Crucis contains just over 100 stars, and is about 10 million years old.
The Jewel Box lies about 7500 light-years away, spannning 20 light-years across. North is to the left.
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| Optics |
20 " Keller cassegrain in corrected secondary focus at f/9 |
| Mount | Liebscher GEM |
| Camera | SBIG STL-11000M at -20C, 8-pos STL filter wheel |
| Filters | Baader RGB |
| Date | May 08, 2008. |
| Location | IAS/Hakos Namibia |
| Sky Conditions |
dark skies, raw FWHM: 1.7-1.9" temperature 10 C, |
| Exposure | R:G:B = 20:20:20 minutes (10-minute sub-exposures); synthetic luminance used |
| Programs used |
Maxim DL 4.5
CCDStack Photoshop CS3 |