How Many Subs

Fireworks Galaxy

NGC 6946, Caldwell 12 · Galaxy in Cygnus

Magnitude
9.6
Size
11′ × 10′
Effective surface brightness
22.7 mag/arcsec²
Best months
Jul, Aug, Sep
Declination
+60°
Filter
None (broadband target)

A face-on spiral famous for its supernovae, dimmed by Milky Way dust. Faint arms; the open cluster NGC 6939 sits nearby.

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 Fireworks 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.
TelescopeIn frameBortle 3 (rural)Bortle 5 (suburban)Bortle 7 (urban edge)
ZWO Seestar S5010 s subs26%1 h 55 min692 subs3 h 15 min1,172 subs9 h 04 min3,267 subs
ZWO Seestar S50 Pro10 s subs13%2 h 09 min772 subs3 h 35 min1,291 subs9 h 53 min3,558 subs
ZWO Seestar S3010 s subs15%2 h 12 min791 subs3 h 32 min1,270 subs9 h 21 min3,366 subs
ZWO Seestar S30 Pro10 s subs8%2 h 18 min830 subs3 h 49 min1,375 subs10 h3,760 subs
DwarfLab DWARF 315 s subs11%2 h 28 min592 subs4 h 31 min1,086 subs14 h3,244 subs
DwarfLab DWARF mini15 s subs15%1 h 54 min456 subs3 h 14 min775 subs9 h 03 min2,172 subs
DwarfLab Draco30 s subs15%1 h 32 min184 subs2 h 39 min318 subs7 h 30 min900 subs
DwarfLab DWARF II15 s subs10%8 h 51 min2,123 subs13 h3,011 subs29 h6,891 subs
Vaonis Vespera II10 s subs13%1 h 55 min692 subs3 h 15 min1,172 subs9 h 04 min3,267 subs
Vaonis Vespera Pro10 s subs11%4 h 47 min1,722 subs7 h 35 min2,730 subs20 h7,136 subs
Vaonis Vespera 310 s subs13%1 h 49 min655 subs3 h 06 min1,115 subs8 h 41 min3,128 subs
Vaonis Vespera Pro 210 s subs11%4 h 30 min1,622 subs7 h 12 min2,590 subs19 h6,822 subs
Unistellar eQuinox 24 s subs32%2 h 45 min2,469 subs3 h 34 min3,216 subs7 h 12 min6,481 subs
Unistellar Odyssey4 s subs33%15 h13,367 subs18 h16,086 subs31 h27,966 subs
Celestron Origin10 s subs21%26 min159 subs49 min295 subs2 h 28 min890 subs
Celestron Origin Mark II10 s subs25%32 min194 subs1 h 05 min390 subs3 h 28 min1,246 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