Andromeda Galaxy

M31, NGC 224 · Galaxy in Andromeda

Magnitude: 3.4
Size: 178′ × 63′
Effective surface brightness: 22.2 mag/arcsec²
Best months: Sep, Oct, Nov
Declination: +41°
Filter: None (broadband target)

The nearest big spiral and the most imaged galaxy in the sky. The core arrives in minutes, the dust lanes in an hour, the faint outer disc needs a whole night. Too big for most smart-scope fields without mosaic.

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 Andromeda Galaxy, 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	4.1× frame	34 min204 subs	55 min332 subs	2 h 29 min893 subs
ZWO Seestar S50 Pro10 s subs	2.1× frame	38 min227 subs	1 h 01 min366 subs	2 h 42 min973 subs
ZWO Seestar S3010 s subs	2.5× frame	38 min231 subs	1 h359 subs	2 h 33 min920 subs
ZWO Seestar S30 Pro10 s subs	1.3× frame	40 min243 subs	1 h 05 min389 subs	2 h 51 min1,028 subs
DwarfLab DWARF 315 s subs	1.8× frame	44 min178 subs	1 h 17 min310 subs	3 h 42 min888 subs
DwarfLab DWARF mini15 s subs	2.5× frame	34 min135 subs	55 min220 subs	2 h 28 min594 subs
DwarfLab Draco30 s subs	2.4× frame	27 min55 subs	45 min90 subs	2 h 03 min246 subs
DwarfLab DWARF II15 s subs	1.7× frame	2 h 31 min603 subs	3 h 30 min840 subs	7 h 50 min1,879 subs
Vaonis Vespera II10 s subs	2.1× frame	34 min204 subs	55 min332 subs	2 h 29 min893 subs
Vaonis Vespera Pro10 s subs	1.8× frame	1 h 23 min500 subs	2 h 08 min770 subs	5 h 25 min1,949 subs
Vaonis Vespera 310 s subs	2.0× frame	32 min193 subs	53 min317 subs	2 h 22 min855 subs
Vaonis Vespera Pro 210 s subs	1.8× frame	1 h 19 min472 subs	2 h 02 min731 subs	5 h 11 min1,864 subs
Unistellar eQuinox 24 s subs	5.2× frame	46 min690 subs	59 min890 subs	1 h 58 min1,764 subs
Unistellar Odyssey4 s subs	5.3× frame	4 h 05 min3,683 subs	4 h 54 min4,410 subs	8 h 26 min7,591 subs
Celestron Origin10 s subs	3.5× frame	8 min48 subs	14 min85 subs	41 min244 subs
Celestron Origin Mark II10 s subs	4.0× frame	10 min60 subs	19 min112 subs	57 min341 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.

Andromeda Galaxy

How long with each smart telescope

Imaging the galaxy

Per-telescope pages