M66

NGC 3627 · Galaxy in Leo

Magnitude: 8.9
Size: 9′ × 4′
Effective surface brightness: 21.4 mag/arcsec²
Best months: Feb, Mar, Apr
Declination: +13°
Filter: None (broadband target)

The brightest of the Leo Triplet, with asymmetric arms from a past encounter.

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 M66, default sub length, recommended filter, and how much of each frame it fills. Click a cell for the full Bortle 1 to 9 table.
Telescope	In frame	Bortle 3 (rural)	Bortle 5 (suburban)	Bortle 7 (urban edge)
ZWO Seestar S5010 s subs	21%	18 min108 subs	27 min163 subs	1 h 07 min405 subs
ZWO Seestar S50 Pro10 s subs	11%	20 min119 subs	30 min179 subs	1 h 13 min441 subs
ZWO Seestar S3010 s subs	13%	20 min119 subs	29 min174 subs	1 h 09 min417 subs
ZWO Seestar S30 Pro10 s subs	7%	21 min127 subs	32 min190 subs	1 h 18 min466 subs
DwarfLab DWARF 315 s subs	9%	24 min97 subs	38 min154 subs	1 h 41 min403 subs
DwarfLab DWARF mini15 s subs	13%	18 min71 subs	27 min108 subs	1 h 07 min270 subs
DwarfLab Draco30 s subs	12%	15 min30 subs	22 min45 subs	56 min112 subs
DwarfLab DWARF II15 s subs	8%	1 h 14 min296 subs	1 h 40 min399 subs	3 h 32 min847 subs
Vaonis Vespera II10 s subs	10%	18 min108 subs	27 min163 subs	1 h 07 min405 subs
Vaonis Vespera Pro10 s subs	9%	43 min257 subs	1 h 02 min373 subs	2 h 27 min882 subs
Vaonis Vespera 310 s subs	10%	17 min102 subs	26 min155 subs	1 h 05 min388 subs
Vaonis Vespera Pro 210 s subs	9%	40 min243 subs	59 min355 subs	2 h 20 min843 subs
Unistellar eQuinox 24 s subs	26%	22 min328 subs	28 min414 subs	53 min792 subs
Unistellar Odyssey4 s subs	27%	1 h 53 min1,699 subs	2 h 14 min2,013 subs	3 h 46 min3,385 subs
Celestron Origin10 s subs	18%	5 min30 subs	7 min42 subs	18 min111 subs
Celestron Origin Mark II10 s subs	20%	6 min34 subs	9 min57 subs	26 min155 subs

Open in the calculator

Imaging the galaxy

Galaxies are broadband targets: their light is mostly starlight spread across the spectrum, so a dual-band filter throws most of it away and makes things slower, not faster. Shoot without a filter (or with a plain UV/IR cut) and rely on total time and a dark sky. The core of a galaxy is usually many times brighter than its outer disc, so a short stack shows the nucleus long before the arms; the figures here are for the arms and disc, not the core.

Field rotation in Alt-Az mode crops the edges of the stack over a long session, so on a big galaxy re-centre now and then or use EQ mode where your scope supports it.

M66

How long with each smart telescope

Imaging the galaxy

Per-telescope pages