NGC 4755, The Jewel Box

Primary identifier: NGC 4755
Other identifiers: Herschel's Jewel Box, C 1250-600, Melotte 114, VdB-H 141, ASA 052
Type: Open cluster
Magnitude: 4.2 V
Diameter: 10'

RA: 12h 53m 42s
Dec: –60° 22' 00''
Constellation: Cru
Charts: U2000 429, MSA 2:988, SA 25, Discover 02,04
Visibility: Feb-Sep

Observer: Richard Ford

Date: 2007 April 14/15 (Sat/Sun)
Location: Cape Town (Fairview Dairy Farm, Conterman's Kloof)
Instrument: 8-inch f/7 (Dobsonian)

Sky conditions: The sky overhead is still dark but with a brightened horizon. Atmosphere is stable and temporary turbulence might be observed. Naked-eye limiting magnitude = 4.5

Description: It is seen as a compact open cluster with individual stars contrasting in different colours which sparkle like a jewellery box. It fairly bright as far as compact open clusters are concerned. It is spectacularly enjoyed at dark sky parties and open nights at the observatory. It is very easy to find. There are over 50 member stars arranged in a compact order of blue, blue-white, white and yellow white stars. In the middle of the open cluster an orange supergiant is discerned. The velocity dispersion is weaker because the individual stars leave small open gaps on the outskirts of the cluster. (Recorded on 2007 April 15, 01:25)

Observer: Carol Botha

Date: 2007 February 13, 21:30
Location: Bellville
Instrument: 8-inch Dobsonian, 25mm eyepiece

Sky conditions: Clear; light pollution

Description: Open cluster in Crux. Small group of different coloured stars, looks just like its name - a jewel box. Three bright stars form a triangle. Halving the triangle are four stars - one bright orange, two almost greenish in colour. Surrounded by fainter stars.