NGC/IC Project Restoration Effort

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NGC4755

 

Basic Information


Location and Magnitude


Right Ascension: 12:53:39.0
Declination: -60:21:42
Constellation: CRU
Visual Magnitude: 4.2

Historic Information


Discoverer: Lacaille
Year of discovery: 1751
Discovery aperture: 0.5

Observational


Summary description: Cl, vL, st vB (κ Crucis)
Sub-type: I3r

Steve's Notes

===== NGC 4755 13.1" (2/20/04 - Costa Rica): at 105x, 120-150 stars are resolved in the Jewel Box cluster with careful viewing as a huge number of mag 13-14 stars form a rich carpet in the background of a half-dozen very bright stars in the cluster. Most prominent is a string of three 6-7th magnitude stars including orange-red DU Crucis (V = 7.2-7.7) with the brightest stars forming a letter "A" asterism. The star distribution is very irregular and a number of stars are arranged in strings, loops, pair and triplets. This small naked-eye cluster is just north of the Coalsack and roughly one degree SE of mag 1.3 Mimosa (Beta Crucis). 12" (6/29/02 - Bargo, Australia): the Jewel Box cluster is a beautiful, naked-eye cluster about a degree SE of Beta Crucis. At 186x, the cluster includes a half-dozen very bright stars (mag 6-7.5) set over a rich background of scores of mag 9-13 stars within a compact 10' diameter. A line of three mag 6-7 crosses the center of cluster from NW to SE with a striking orange-red star (DU Crucis = SAO 252073) near the center. Other stars have blue-white and yellow-whites tints, though these are more subdued. To the south of the cluster is the remarkable 6¡x4¡ oval dark Coalsack which sits adjacent to the SE side of the Southern Cross.