How Many Subs

Sombrero Galaxy

M104, NGC 4594 · Galaxy in Virgo

Magnitude
8.0
Size
9′ × 4′
Effective surface brightness
21.5 mag/arcsec²
Best months
Mar, Apr, May
Declination
-12°
Filter
None (broadband target)

The bright bulge and knife-edge dust lane are obvious within an hour. Low from northern Europe, so catch it near the meridian.

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 Sombrero Galaxy, default sub length, recommended filter. Click a cell for the full Bortle 1 to 9 table.
TelescopeBortle 3 (rural)Bortle 5 (suburban)Bortle 7 (urban edge)
ZWO Seestar S5010 s subs26 min159 subs37 min224 subs1 h 24 min504 subs
ZWO Seestar S50 Pro10 s subs22 min135 subs34 min204 subs1 h 25 min508 subs
ZWO Seestar S3010 s subs20 min122 subs31 min186 subs1 h 18 min467 subs
ZWO Seestar S30 Pro10 s subs24 min144 subs36 min217 subs1 h 29 min537 subs
DwarfLab Dwarf 315 s subs32 min130 subs49 min196 subs2 h 01 min485 subs
DwarfLab Dwarf Mini15 s subs19 min75 subs29 min117 subs1 h 16 min305 subs
DwarfLab Dwarf II15 s subs1 h 24 min338 subs1 h 54 min457 subs4 h 04 min977 subs
Vaonis Vespera II10 s subs20 min122 subs31 min186 subs1 h 18 min467 subs
Vaonis Vespera Pro10 s subs56 min339 subs1 h 19 min474 subs2 h 57 min1,064 subs
Unistellar eQuinox 24 s subs25 min376 subs32 min476 subs1 h 01 min913 subs
Unistellar Odyssey4 s subs2 h 10 min1,953 subs2 h 34 min2,317 subs4 h 21 min3,909 subs
Celestron Origin10 s subs5 min30 subs8 min48 subs21 min128 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.

Per-telescope pages