How long to image the Andromeda Galaxy with the ZWO Seestar S50
From a Bortle 6 suburban sky, the ZWO Seestar S50 needs about 1 h 27 min (525 subs of 10 s) for a solid image of the Andromeda Galaxy. A quick look takes 22 min; a showpiece 5 h 50 min. Under a Bortle 3 rural sky the solid figure drops to 34 min. At Bortle 6 the limit is skyglow, so a darker site or a filter helps more than longer subs. In this scope's field it is 4.1× wider than the frame.
| Sky | Quick lookTarget obvious, still noisy | SolidClean enough to share | ShowpieceSmooth faint detail, print-worthy |
|---|---|---|---|
| Bortle 1Excellent dark site | 7 min44 subs | 29 min173 subs | 1 h 55 min689 subs |
| Bortle 2Typical dark site | 8 min46 subs | 31 min184 subs | 2 h 02 min733 subs |
| Bortle 3Rural | 8 min51 subs | 34 min204 subs | 2 h 16 min815 subs |
| Bortle 4Rural / suburban transition | 11 min64 subs | 42 min254 subs | 2 h 49 min1,013 subs |
| Bortle 5Suburban | 14 min83 subs | 55 min332 subs | 3 h 41 min1,328 subs |
| Bortle 6Bright suburban | 22 min132 subs | 1 h 27 min525 subs | 5 h 50 min2,100 subs |
| Bortle 7Suburban / urban transition | 37 min224 subs | 2 h 29 min893 subs | 9 h 55 min3,572 subs |
| Bortle 8City | 1 h 01 min367 subs | 4 h 04 min1,465 subs | 16 h5,857 subs |
| Bortle 9Inner city | 1 h 52 min671 subs | 7 h 27 min2,683 subs | 30 h10,729 subs |
Power and kit for this session
Allowing for slewing, focusing and rejected subs, that is about 1 h 54 min of run time. The Seestar S50’s battery (rated about 6 h) should cover it; a power bank still keeps the phone running the app alive. (Bortle 6, solid image; we allow 30% over the integration time.)
- USB-C power bank 20000mAh 5V 3AThe S50 draws 5 V 3 A over USB-C and runs while charging; no PD needed.
- Seestar S50 dew shieldThe built-in heater copes with most nights; a shield helps in heavy dew and blocks stray light.
- red LED head torchRed light keeps your night vision; white light costs you twenty minutes of dark adaptation every time.
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Everything that fits the Seestar S50 →
How it frames
The Andromeda Galaxy is 178′ × 63′ across. The Seestar S50 frames 1.28° × 0.72° at 2.39″ per pixel, so it is 4.1× wider than the frame. A mosaic, or choosing the part you want and letting the rest go, is how it gets shot on this scope.
Longer subs
10, 20 and 30 s in Alt-Az; 60 s only in EQ mode (app 2.5 and later). Time for a solid image by sub length:
| Sub length | Bortle 3 | Bortle 5 | Bortle 7 |
|---|---|---|---|
| 10 s | 34 min204 subs | 55 min332 subs | 2 h 29 min893 subs |
| 20 s | 29 min87 subs | 50 min151 subs | 2 h 24 min432 subs |
| 30 s | 27 min55 subs | 49 min98 subs | 2 h 22 min285 subs |
| 60 s | 30 min30 subs | 47 min47 subs | 2 h 20 min141 subs |
Leave the dual-band filter out for the Andromeda Galaxy. It is a galaxy, and it shines right across the spectrum. A dual-band filter keeps two emission lines and throws the rest away, so most of the light you came for is being stopped along with the sky. From a Bortle 6 sky it would be roughly 12 times slower.
About the Andromeda Galaxy
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.
M31, NGC 224 · Galaxy in Andromeda · magnitude 3.4 · 178′ × 63′ · best in Sep, Oct, Nov. Reachable from mid-northern latitudes (UK, northern US, central Europe) and from the south.
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.
About the ZWO Seestar S50
The scope that made smart astrophotography mainstream. 50 mm triplet, 2 MP sensor, dual-band filter on a wheel. Alt-Az stacking at 10 s, EQ mode unlocks 60 s. Out of production since 2026 and replaced by the S50 Pro, but there are a great many in use.
10, 20 and 30 s in Alt-Az; 60 s only in EQ mode (app 2.5 and later). Built-in dual-band light-pollution filter, switchable in the app.
Longer subs matter most under dark skies, where read noise rather than skyglow sets the floor. From a city the difference between 10 s and 60 s subs is small; from a rural site it can halve the total time, especially with a dual-band filter in place.
Stack across nights. Every smart scope app can continue a stack or you can combine the saved frames on a computer; the figures here are totals, not single-session limits.
Have an image of the Andromeda Galaxy from a Seestar S50? Email it with your total time and sky to [email protected] and it goes here, credited.
Same target, other telescopes
- Andromeda Galaxy with the ZWO Seestar S50 Pro: 1 h 36 min from Bortle 6
- Andromeda Galaxy with the ZWO Seestar S30: 1 h 32 min from Bortle 6
- Andromeda Galaxy with the ZWO Seestar S30 Pro: 1 h 41 min from Bortle 6
- Andromeda Galaxy with the DwarfLab DWARF 3: 2 h 07 min from Bortle 6
- Andromeda Galaxy with the DwarfLab DWARF mini: 1 h 27 min from Bortle 6
- Andromeda Galaxy with the DwarfLab Draco: 1 h 12 min from Bortle 6
- Andromeda Galaxy with the DwarfLab DWARF II: 4 h 59 min from Bortle 6
- Andromeda Galaxy with the Vaonis Vespera II: 1 h 27 min from Bortle 6
- Andromeda Galaxy with the Vaonis Vespera Pro: 3 h 16 min from Bortle 6
- Andromeda Galaxy with the Vaonis Vespera 3: 1 h 24 min from Bortle 6
- Andromeda Galaxy with the Vaonis Vespera Pro 2: 3 h 07 min from Bortle 6
- Andromeda Galaxy with the Unistellar eQuinox 2: 1 h 19 min from Bortle 6
- Andromeda Galaxy with the Unistellar Odyssey: 6 h 07 min from Bortle 6
- Andromeda Galaxy with the Celestron Origin: 23 min from Bortle 6
- Andromeda Galaxy with the Celestron Origin Mark II: 32 min from Bortle 6
All telescopes for the Andromeda Galaxy · All targets for the Seestar S50