How long to image the Andromeda Galaxy with the ZWO Seestar S30 Pro
From a Bortle 6 suburban sky, the ZWO Seestar S30 Pro needs about 1 h 41 min (609 subs of 10 s) for a solid image of the Andromeda Galaxy. A quick look takes 25 min; a showpiece 6 h 46 min. Under a Bortle 3 rural sky the solid figure drops to 40 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 just over the frame at 1.3×.
| Sky | Quick lookTarget obvious, still noisy | SolidClean enough to share | ShowpieceSmooth faint detail, print-worthy |
|---|---|---|---|
| Bortle 1Excellent dark site | 9 min52 subs | 35 min208 subs | 2 h 18 min830 subs |
| Bortle 2Typical dark site | 9 min55 subs | 37 min220 subs | 2 h 26 min879 subs |
| Bortle 3Rural | 10 min61 subs | 40 min243 subs | 2 h 42 min972 subs |
| Bortle 4Rural / suburban transition | 12 min75 subs | 50 min300 subs | 3 h 20 min1,198 subs |
| Bortle 5Suburban | 16 min98 subs | 1 h 05 min389 subs | 4 h 19 min1,556 subs |
| Bortle 6Bright suburban | 25 min153 subs | 1 h 41 min609 subs | 6 h 46 min2,435 subs |
| Bortle 7Suburban / urban transition | 43 min257 subs | 2 h 51 min1,028 subs | 11 h4,109 subs |
| Bortle 8City | 1 h 10 min420 subs | 4 h 40 min1,678 subs | 19 h6,709 subs |
| Bortle 9Inner city | 2 h 08 min766 subs | 8 h 31 min3,064 subs | 34 h12,253 subs |
Power and kit for this session
Allowing for slewing, focusing and rejected subs, that is about 2 h 12 min of run time. The Seestar S30 Pro’s battery (rated about 5 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 10000mAh 5V 3A5 V 3 A input and it runs while charging.
- Seestar S30 Pro dew shieldActive anti-dew is built in; a shield adds margin. The S30 Pro front differs from the S30, so check the listing.
- 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 S30 Pro →
How it frames
The Andromeda Galaxy is 178′ × 63′ across. The Seestar S30 Pro frames 3.99° × 2.24° at 3.74″ per pixel, so it is just over the frame at 1.3×. Point at the part you want; the edges will fall outside the frame.
Longer subs
10, 20 and 30 s in Alt-Az; 60 s only in EQ mode, which needs the TH10 head. Time for a solid image by sub length:
| Sub length | Bortle 3 | Bortle 5 | Bortle 7 |
|---|---|---|---|
| 10 s | 40 min243 subs | 1 h 05 min389 subs | 2 h 51 min1,028 subs |
| 20 s | 34 min103 subs | 58 min176 subs | 2 h 45 min495 subs |
| 30 s | 32 min64 subs | 56 min113 subs | 2 h 43 min326 subs |
| 60 s | 30 min30 subs | 54 min55 subs | 2 h 40 min161 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 S30 Pro
The S30 optics upgraded to a quadruplet in front of an 8 MP IMX585. Same speed per pixel as the S30, four times the pixels, so you can crop hard.
10, 20 and 30 s in Alt-Az; 60 s only in EQ mode, which needs the TH10 head. Built-in UV/IR-cut, dual-band (OIII 30 nm / Hα 20 nm) and dark filters on the telephoto camera.
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 S30 Pro? 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: 1 h 27 min from Bortle 6
- 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 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 S30 Pro