Cookie consent

AstroBin saves small pieces of text information (cookies) on your device in order to deliver better content and for statistical purposes. You can disable the usage of cookies by changing the settings of your browser. By browsing AstroBin without changing the browser settings, you grant us permission to store that information on your device.

I agree
Contains:  kappa Cru cluster, Jewel Box, NGC 4755, The star κCru
Getting plate-solving status, please wait...
Jewel Box NGC 4755, 


            Barry Brook
Jewel Box NGC 4755

Jewel Box NGC 4755

Technical card

Resolution: 2405x1723

Dates:Feb. 6, 2015

Frames:ZWO optical ZWO RGBL Filters: 160x10" (gain: 95.00) bin 1x1

Integration: 0.4 hours

Darks: ~100

Flats: ~100

Bias: ~200

Avg. Moon age: 17.02 days

Avg. Moon phase: 94.35%

Bortle Dark-Sky Scale: 2.00

Temperature: 6.00 job: 563443

RA center: 193.425 degrees

DEC center: -60.341 degrees

Pixel scale: 1.026 arcsec/pixel

Orientation: 13.797 degrees

Field radius: 0.421 degrees

Locations: Huon Ridge Observatory, Judbury, Tasmania, Australia


The Jewel Box is a small open cluster in Crux, near the bright star Beta Crucis and the Coalsack Nebula. Situated 6,400 light years from the Sun, it is only about 16 million years old.

This was a test image, to assess the DSO capability of my ZWO ASI120MM guide camera. It is uncooled, and really meant for planetary imaging and as a sensitive autoguider (the main purpose I put it to!), but I thought it might be fun to try it out. I had the gain turned up high so that I could take short images, as these were unguided. Overall it was moderately successful, though there is star bloat.

40 x 10 sec for L, R, G and B

The 2nd image (B) is processed just using the RGB data (i.e. no luminance channel).



Barry Brook
License: Attribution Creative Commons


  • Final
    Jewel Box NGC 4755, 


            Barry Brook
  • Jewel Box NGC 4755, 


            Barry Brook

Sky plot

Sky plot


Jewel Box NGC 4755, 


            Barry Brook