How long to image the Fireworks Galaxy with the ZWO Seestar S30 Pro
From a Bortle 6 suburban sky, the ZWO Seestar S30 Pro needs about 6 h 06 min (2,196 subs of 10 s) for a solid image of the Fireworks Galaxy. A quick look takes 1 h 31 min; a showpiece 24 h. Under a Bortle 3 rural sky the solid figure drops to 2 h 18 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 fills 8% of the frame’s short side.
| Sky | Quick lookTarget obvious, still noisy | SolidClean enough to share | ShowpieceSmooth faint detail, print-worthy |
|---|---|---|---|
| Bortle 1Excellent dark site | 29 min175 subs | 1 h 56 min697 subs | 7 h 44 min2,785 subs |
| Bortle 2Typical dark site | 31 min186 subs | 2 h 04 min743 subs | 8 h 15 min2,969 subs |
| Bortle 3Rural | 35 min208 subs | 2 h 18 min830 subs | 9 h 13 min3,317 subs |
| Bortle 4Rural / suburban transition | 43 min261 subs | 2 h 53 min1,041 subs | 12 h4,162 subs |
| Bortle 5Suburban | 57 min344 subs | 3 h 49 min1,375 subs | 15 h5,500 subs |
| Bortle 6Bright suburban | 1 h 31 min549 subs | 6 h 06 min2,196 subs | 24 h8,782 subs |
| Bortle 7Suburban / urban transition | 2 h 37 min940 subs | 10 h3,760 subs | 42 h15,037 subs |
| Bortle 8City | 4 h 18 min1,547 subs | 17 h6,188 subs | 69 h24,749 subs |
| Bortle 9Inner city | 7 h 54 min2,842 subs | 32 h11,366 subs | 130+ h45,461 subs |
Power and kit for this session
Allowing for slewing, focusing and rejected subs, that is about 7 h 56 min of run time. That is more than one night: over 2 nights, about 3 h 58 min each. The Seestar S30 Pro’s battery (rated about 5 h) should cover each night; 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 Fireworks Galaxy is 11′ × 10′ across. The Seestar S30 Pro frames 3.99° × 2.24° at 3.74″ per pixel, so it fills 8% of the frame’s short side.
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 | 2 h 18 min830 subs | 3 h 49 min1,375 subs | 10 h3,760 subs |
| 20 s | 1 h 54 min342 subs | 3 h 25 min615 subs | 10 h1,807 subs |
| 30 s | 1 h 46 min212 subs | 3 h 17 min394 subs | 9 h 54 min1,189 subs |
| 60 s | 1 h 38 min98 subs | 3 h 09 min189 subs | 9 h 46 min587 subs |
Leave the dual-band filter out for the Fireworks 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 13 times slower.
About the Fireworks Galaxy
A face-on spiral famous for its supernovae, dimmed by Milky Way dust. Faint arms; the open cluster NGC 6939 sits nearby.
NGC 6946, Caldwell 12 · Galaxy in Cygnus · magnitude 9.6 · 11′ × 10′ · best in Jul, Aug, Sep. 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 Fireworks 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
- Fireworks Galaxy with the ZWO Seestar S50: 5 h 15 min from Bortle 6
- Fireworks Galaxy with the ZWO Seestar S50 Pro: 5 h 45 min from Bortle 6
- Fireworks Galaxy with the ZWO Seestar S30: 5 h 32 min from Bortle 6
- Fireworks Galaxy with the DwarfLab DWARF 3: 7 h 37 min from Bortle 6
- Fireworks Galaxy with the DwarfLab DWARF mini: 5 h 14 min from Bortle 6
- Fireworks Galaxy with the DwarfLab Draco: 4 h 19 min from Bortle 6
- Fireworks Galaxy with the DwarfLab DWARF II: 18 h from Bortle 6
- Fireworks Galaxy with the Vaonis Vespera II: 5 h 15 min from Bortle 6
- Fireworks Galaxy with the Vaonis Vespera Pro: 12 h from Bortle 6
- Fireworks Galaxy with the Vaonis Vespera 3: 5 h 01 min from Bortle 6
- Fireworks Galaxy with the Vaonis Vespera Pro 2: 11 h from Bortle 6
- Fireworks Galaxy with the Unistellar eQuinox 2: 4 h 49 min from Bortle 6
- Fireworks Galaxy with the Unistellar Odyssey: 22 h from Bortle 6
- Fireworks Galaxy with the Celestron Origin: 1 h 23 min from Bortle 6
- Fireworks Galaxy with the Celestron Origin Mark II: 1 h 54 min from Bortle 6
All telescopes for the Fireworks Galaxy · All targets for the Seestar S30 Pro