How long to image the North America Nebula with the ZWO Seestar S50
From a Bortle 6 suburban sky, the ZWO Seestar S50 needs about 1 h 25 min (512 subs of 10 s with the built-in dual-band (LP filter) filter) for a solid image of the North America Nebula. A quick look takes 21 min; a showpiece 5 h 41 min. Under a Bortle 3 rural sky the solid figure drops to 59 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 | 14 min86 subs | 57 min342 subs | 3 h 48 min1,366 subs |
| Bortle 2Typical dark site | 14 min87 subs | 58 min347 subs | 3 h 51 min1,387 subs |
| Bortle 3Rural | 15 min90 subs | 59 min357 subs | 3 h 58 min1,427 subs |
| Bortle 4Rural / suburban transition | 16 min96 subs | 1 h 03 min381 subs | 4 h 14 min1,523 subs |
| Bortle 5Suburban | 17 min105 subs | 1 h 10 min419 subs | 4 h 39 min1,674 subs |
| Bortle 6Bright suburban | 21 min128 subs | 1 h 25 min512 subs | 5 h 41 min2,047 subs |
| Bortle 7Suburban / urban transition | 29 min173 subs | 1 h 55 min690 subs | 7 h 39 min2,757 subs |
| Bortle 8City | 40 min242 subs | 2 h 41 min965 subs | 11 h3,860 subs |
| Bortle 9Inner city | 1 h 05 min389 subs | 4 h 19 min1,553 subs | 17 h6,212 subs |
Power and kit for this session
Allowing for slewing, focusing and rejected subs, that is about 1 h 51 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 North America Nebula is 120′ × 100′ 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 | 59 min357 subs | 1 h 10 min419 subs | 1 h 55 min690 subs |
| 20 s | 43 min130 subs | 54 min161 subs | 1 h 39 min297 subs |
| 30 s | 38 min76 subs | 48 min97 subs | 1 h 33 min187 subs |
| 60 s | 33 min33 subs | 43 min43 subs | 1 h 28 min89 subs |
With and without the dual-band filter
| Filter | Bortle 3 | Bortle 5 | Bortle 7 |
|---|---|---|---|
| UV/IR-cut (no light-pollution filter) | 51 min306 subs | 1 h 25 min509 subs | 3 h 52 min1,393 subs |
| dual-band (LP filter) | 59 min357 subs | 1 h 10 min419 subs | 1 h 55 min690 subs |
About the North America Nebula
A huge emission cloud next to Deneb shaped like the continent. The Cygnus Wall is the bright bit; a dual-band filter and a wide field make it one of the best summer targets from town.
NGC 7000, Caldwell 20 · Emission nebula in Cygnus · magnitude 4.0 · 120′ × 100′ · best in Jul, Aug, Sep. Reachable from mid-northern latitudes (UK, northern US, central Europe) and from the south.
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 North America 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
- North America Nebula with the ZWO Seestar S50 Pro: 1 h 36 min from Bortle 6
- North America Nebula with the ZWO Seestar S30: 1 h 39 min from Bortle 6
- North America Nebula with the ZWO Seestar S30 Pro: 1 h 43 min from Bortle 6
- North America Nebula with the DwarfLab DWARF 3: 1 h 46 min from Bortle 6
- North America Nebula with the DwarfLab DWARF mini: 1 h 24 min from Bortle 6
- North America Nebula with the DwarfLab Draco: 1 h 08 min from Bortle 6
- North America Nebula with the DwarfLab DWARF II: 7 h 45 min from Bortle 6
- North America Nebula with the Vaonis Vespera II: 2 h 15 min from Bortle 6
- North America Nebula with the Vaonis Vespera Pro: 5 h 04 min from Bortle 6
- North America Nebula with the Vaonis Vespera 3: 2 h 09 min from Bortle 6
- North America Nebula with the Vaonis Vespera Pro 2: 4 h 49 min from Bortle 6
- North America Nebula with the Unistellar eQuinox 2: 2 h 04 min from Bortle 6
- North America Nebula with the Unistellar Odyssey: 9 h 33 min from Bortle 6
- North America Nebula with the Celestron Origin: 36 min from Bortle 6
- North America Nebula with the Celestron Origin Mark II: 49 min from Bortle 6
All telescopes for the North America Nebula · All targets for the Seestar S50