M46 (NGC 2437) Pup open cluster Difficulty
level 1NGC 2438 Pup planetary nebula Difficulty level 3
Date of observation: 1998/11/21 03:29
Observing site: Hoshinomura
Transparency/seeing/sky darkness: 1/4/3
Instruments: 32cm Dobsonian with Er32 at 50x
Width of field: 1‹
This is a large and bright open cluster. Even at 50x it is almost completely resolved. This fine cluster is filled with numerous pin-points of faint stars and very difficult to draw. This sketch shows it as nebulosity. There are also many bright stars embedded in this cluster. The neighboring M47 makes a good contrast with M46. M47 has fewer stars with unequal brightness. M46 presents itself as a dainty cluster while M47 shows its coarseness. Another similarly contrasting pair is NGC 2451 and NGC 2477 in Puppis. They are more contrasting than the M46 and M47 pair.
At this magnification the planetary nebula NGC 2438 is clearly seen. Its image overlapping with the open cluster is mysterious and unreal. It is rather large as planetary nebulae go. Switching to high powers a ring structure becomes clearer. This nebula is interesting by itself but it is usually viewed in association with M46 playing second fiddle to it.