M46

NGC 2437 · Open cluster in Puppis

Magnitude
6.1
Size
27′
Effective surface brightness
20.0 mag/arcsec²
Best months
Dec, Jan, Feb
Declination
-15°
Filter
None (broadband target)

A rich open cluster with the planetary nebula NGC 2438 apparently embedded in it. Dual-band lifts the little ring.

Reachable from mid-northern latitudes (UK, northern US, central Europe) and from the south.

How long with each smart telescope

Total integration for a solid image of the M46, default sub length, recommended filter, and how much of each frame it fills. Click a cell for the full Bortle 1 to 9 table.
TelescopeIn frameBortle 3 (rural)Bortle 5 (suburban)Bortle 7 (urban edge)
ZWO Seestar S5010 s subs63%5 min30 subs5 min30 subs5 min30 subs
ZWO Seestar S50 Pro10 s subs33%5 min30 subs5 min30 subs5 min30 subs
ZWO Seestar S3010 s subs38%5 min30 subs5 min30 subs5 min30 subs
ZWO Seestar S30 Pro10 s subs20%5 min30 subs5 min30 subs5 min30 subs
DwarfLab DWARF 315 s subs27%8 min30 subs8 min30 subs8 min30 subs
DwarfLab DWARF mini15 s subs38%8 min30 subs8 min30 subs8 min30 subs
DwarfLab Draco30 s subs36%15 min30 subs15 min30 subs15 min30 subs
DwarfLab DWARF II15 s subs25%8 min30 subs8 min30 subs11 min46 subs
Vaonis Vespera II10 s subs31%5 min30 subs5 min30 subs5 min30 subs
Vaonis Vespera Pro10 s subs28%5 min30 subs5 min30 subs8 min49 subs
Vaonis Vespera 310 s subs31%5 min30 subs5 min30 subs5 min30 subs
Vaonis Vespera Pro 210 s subs27%5 min30 subs5 min30 subs8 min47 subs
Unistellar eQuinox 24 s subs79%2 min30 subs2 min30 subs3 min43 subs
Unistellar Odyssey4 s subs80%7 min102 subs8 min115 subs12 min176 subs
Celestron Origin10 s subs53%5 min30 subs5 min30 subs5 min30 subs
Celestron Origin Mark II10 s subs60%5 min30 subs5 min30 subs5 min30 subs

Open in the calculator

Imaging the open cluster

Open clusters are the easiest targets in the sky. The stars are bright, so the aim is colour and tight stars rather than depth: short subs, no filter, and stop before the bright members saturate. The nominal time here gets you clean star colour; more integration only adds background stars.

Per-telescope pages