How long to image the Carina Nebula with the ZWO Seestar S50
From a Bortle 6 suburban sky, the ZWO Seestar S50 needs about 9 min (56 subs of 10 s with the built-in dual-band (LP filter) filter) for a solid image of the Carina Nebula. A quick look takes 2 min; a showpiece 37 min. Under a Bortle 3 rural sky the solid figure drops to 7 min. At Bortle 6 the limit is a mix of skyglow and read noise. In this scope's field it is 2.8× wider than the frame.
| Sky | Quick lookTarget obvious, still noisy | SolidClean enough to share | ShowpieceSmooth faint detail, print-worthy |
|---|---|---|---|
| Bortle 1Excellent dark site | 2 min11 subs | 7 min43 subs | 28 min171 subs |
| Bortle 2Typical dark site | 2 min11 subs | 7 min43 subs | 29 min172 subs |
| Bortle 3Rural | 2 min11 subs | 7 min44 subs | 29 min175 subs |
| Bortle 4Rural / suburban transition | 2 min12 subs | 8 min46 subs | 30 min183 subs |
| Bortle 5Suburban | 2 min13 subs | 8 min49 subs | 32 min194 subs |
| Bortle 6Bright suburban | 2 min14 subs | 9 min56 subs | 37 min222 subs |
| Bortle 7Suburban / urban transition | 3 min18 subs | 11 min69 subs | 46 min276 subs |
| Bortle 8City | 4 min23 subs | 15 min90 subs | 1 h360 subs |
| Bortle 9Inner city | 6 min34 subs | 22 min135 subs | 1 h 30 min538 subs |
Power and kit for this session
Allowing for slewing, focusing and rejected subs, that is about 12 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 Carina Nebula is 120′ across. The Seestar S50 frames 1.28° × 0.72° at 2.39″ per pixel, so it is 2.8× 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 | 7 min44 subs | 8 min49 subs | 11 min69 subs |
| 20 s | 10 min30 subs | 10 min30 subs | 10 min31 subs |
| 30 s | 15 min30 subs | 15 min30 subs | 15 min30 subs |
| 60 s | 30 min30 subs | 30 min30 subs | 30 min30 subs |
With and without the dual-band filter
| Filter | Bortle 3 | Bortle 5 | Bortle 7 |
|---|---|---|---|
| UV/IR-cut (no light-pollution filter) | 6 min35 subs | 8 min51 subs | 20 min118 subs |
| dual-band (LP filter) | 7 min44 subs | 8 min49 subs | 11 min69 subs |
About the Carina Nebula
Four times the size and brightness of the Orion Nebula, the best emission nebula in the sky. Southern hemisphere only, and easy from anywhere it rises.
NGC 3372, Caldwell 92, Eta Carinae Nebula · Emission nebula in Carina · magnitude 1.0 · 120′ · best in Feb, Mar, Apr. Low or below the horizon from northern Europe; best from the southern US southwards.
Emission nebulae glow in a few narrow lines, mostly hydrogen-alpha (deep red) and doubly ionised oxygen (teal). A dual-band filter passes those lines and blocks most skyglow, which is why it cuts the time needed from a suburban sky so dramatically. Use it. From a genuinely dark site the gain is smaller because there is less skyglow to block, and read noise becomes the limit, which is where longer subs (EQ mode, or Expert Mode on a Vespera) earn their keep.
Stars lose colour through a dual-band filter; a short broadband stack blended in fixes that if you care.
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 Carina Nebula from a Seestar S50? Email it with your total time and sky to [email protected] and it goes here, credited.
Same target, other telescopes
- Carina Nebula with the ZWO Seestar S50 Pro: 10 min from Bortle 6
- Carina Nebula with the ZWO Seestar S30: 10 min from Bortle 6
- Carina Nebula with the ZWO Seestar S30 Pro: 11 min from Bortle 6
- Carina Nebula with the DwarfLab DWARF 3: 12 min from Bortle 6
- Carina Nebula with the DwarfLab DWARF mini: 9 min from Bortle 6
- Carina Nebula with the DwarfLab Draco: 15 min from Bortle 6
- Carina Nebula with the DwarfLab DWARF II: 41 min from Bortle 6
- Carina Nebula with the Vaonis Vespera II: 12 min from Bortle 6
- Carina Nebula with the Vaonis Vespera Pro: 27 min from Bortle 6
- Carina Nebula with the Vaonis Vespera 3: 12 min from Bortle 6
- Carina Nebula with the Vaonis Vespera Pro 2: 26 min from Bortle 6
- Carina Nebula with the Unistellar eQuinox 2: 11 min from Bortle 6
- Carina Nebula with the Unistellar Odyssey: 48 min from Bortle 6
- Carina Nebula with the Celestron Origin: 5 min from Bortle 6
- Carina Nebula with the Celestron Origin Mark II: 5 min from Bortle 6
All telescopes for the Carina Nebula · All targets for the Seestar S50