How Many Subs

M90

NGC 4569 · Galaxy in Virgo

Magnitude
9.5
Size
9.5′ × 4.5′
Effective surface brightness
22.2 mag/arcsec²
Best months
Mar, Apr, May
Declination
+13°
Filter
None (broadband target)

A large spiral whose arms have been stripped by the cluster medium. Smooth and elongated.

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 M90, 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 subs22%58 min351 subs1 h 36 min574 subs4 h 18 min1,551 subs
ZWO Seestar S50 Pro10 s subs11%1 h 05 min391 subs1 h 45 min632 subs4 h 41 min1,688 subs
ZWO Seestar S3010 s subs13%1 h 06 min397 subs1 h 43 min620 subs4 h 26 min1,597 subs
ZWO Seestar S30 Pro10 s subs7%1 h 10 min419 subs1 h 52 min673 subs4 h 57 min1,784 subs
DwarfLab DWARF 315 s subs10%1 h 16 min305 subs2 h 14 min535 subs6 h 25 min1,541 subs
DwarfLab DWARF mini15 s subs13%58 min231 subs1 h 35 min380 subs4 h 18 min1,031 subs
DwarfLab Draco30 s subs13%47 min94 subs1 h 18 min156 subs3 h 33 min427 subs
DwarfLab DWARF II15 s subs9%4 h 20 min1,042 subs6 h 04 min1,455 subs14 h3,263 subs
Vaonis Vespera II10 s subs11%58 min351 subs1 h 36 min574 subs4 h 18 min1,551 subs
Vaonis Vespera Pro10 s subs10%2 h 24 min862 subs3 h 42 min1,332 subs9 h 24 min3,385 subs
Vaonis Vespera 310 s subs11%55 min332 subs1 h 31 min547 subs4 h 07 min1,485 subs
Vaonis Vespera Pro 210 s subs10%2 h 15 min813 subs3 h 31 min1,264 subs8 h 59 min3,236 subs
Unistellar eQuinox 24 s subs28%1 h 20 min1,195 subs1 h 43 min1,543 subs3 h 24 min3,064 subs
Unistellar Odyssey4 s subs28%7 h 06 min6,389 subs8 h 30 min7,655 subs15 h13,191 subs
Celestron Origin10 s subs19%14 min82 subs24 min146 subs1 h 10 min423 subs
Celestron Origin Mark II10 s subs21%17 min102 subs32 min193 subs1 h 39 min592 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