M 46 (OC)
Open Cluster in Puppis
| R.A. | Dec. | Size | Mag | SB | Cnt.St | Type | Distance | Chart |
|---|---|---|---|---|---|---|---|---|
| 07h 41m 45.8s | -14° 48′ 47.3″ | 20.0′ | 6.1 | 12.3 | III2m | OC | -- | -- |
Source: POSS-2 UK Schmidt Red (STScI) | Field: 30′ × 30′
Background
M46 is a rich, even open cluster 5,400 light-years away in Puppis. About 300 million years old, it contains some 500 members. Its claim to fame for visual observers is the apparent inclusion of the planetary nebula NGC 2438 in the field — a foreground object superimposed on the cluster.
My Observing Notes
25-cm (Meade 10-inch LX200, The Coffee Grinder): One of my Puppis favourites. A bright open cluster with an even dispersion of stars across the whole field of view. The ghostly greyish disk of NGC 2438 floating amongst the stars makes this field unforgettable.(Friday, April 2025)
References
Charts
Ultra-wide view (~25° field)
Wide-field view with Telrad rings (4°, 2°, 0.5°)
Finderscope view (9×50 RACI, ~4.4° TFOV)
Eyepiece view — 35 mm Panoptic on 12-inch f/5 (1.6° TFOV)