Messier 46

46 final

Object:   M46 (NGC 2437) Date:               2019 February 26
Type:              Open cluster
Constellation:           Puppis Time & altitude:        21.30 UT     24º
Catalogue data: Seeing (5 high):                               4/5
            R.A:                7h 42m Transparency (5 high):                   4/5
            Dec:                -14º 49 Telescope:     0.5m f4.1  Dob.
            Magnitude     6.1 Eyepiece       17mm Ethos              x120
            Size (mins)    27 Filters:            None


M46 is almost invisible in the 50mm finder, just a faint smudge. It half-fills the 50 arcmin field of the 17mm Ethos. The cluster is round and I estimate over 200 stars in a small magnitude range sprinkled evenly across it.

Between us and the cluster is the planetary nebula NGC 2438. It is 11th magnitude and roughly 1 arcmin in diameter. I was expecting this to be really difficult like the one in M15, but no, it is very obvious. The drawing records the nebula, viewed at x260. One star was visible on the face of the nebula, NW of the centre. This is not the central star which has a visual magnitude around 16.