NGC 4755 (OC)
| R.A. | Dec. | Size | Mag | SB | Cnt.St | Type | Distance | Chart |
|---|---|---|---|---|---|---|---|---|
| 12h 53m 41.3s | -60° 21′ 53.2″ | 10.0′ | 4.2 | 8.9 | I3r | OC | -- | -- |
Background
NGC 4755 is the famous “Jewel Box” (or κ Crucis Cluster) — a young ( 14 Myr) open cluster of brilliant blue–white stars with a striking red supergiant at its centre. About 6,400 light-years away in Crux. The 4th-magnitude naked-eye glow next to β Crucis is one of the great showpieces of the southern sky.
My Observing Notes
25-cm (Meade 10-inch LX200, The Coffee Grinder): Mentioned as the obvious Crux highlight while seeking out NGC 4337 — not described in detail this session. (Detailed observations to follow in later editions.)(Thursday, April 2025)
25-cm (Club 10-inch LX200), β Cru region: Visited in passing while admiring DY Crucis (also called Ruby Crucis) — an 8.4–8.9 mag carbon star sitting just below β Cru that I had never noticed despite countless trips to the Jewel Box. Pointed out by Rodney Watters; the deep copper-red of DY Cru is unmistakable in the same field once you know to look for it.(Saturday, June 2025)
References
Charts
