How long to image the Tulip Nebula with the ZWO Seestar S50
From a Bortle 6 suburban sky, the ZWO Seestar S50 needs about 2 h 22 min (855 subs of 10 s with the built-in dual-band (LP filter) filter) for a solid image of the Tulip Nebula. A quick look takes 36 min; a showpiece 9 h 29 min. Under a Bortle 3 rural sky the solid figure drops to 1 h 37 min. At Bortle 6 the limit is a mix of skyglow and read noise. In this scope's field it fills 37% 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 | 23 min140 subs | 1 h 33 min559 subs | 6 h 12 min2,234 subs |
| Bortle 2Typical dark site | 24 min142 subs | 1 h 35 min568 subs | 6 h 18 min2,270 subs |
| Bortle 3Rural | 24 min147 subs | 1 h 37 min585 subs | 6 h 30 min2,339 subs |
| Bortle 4Rural / suburban transition | 26 min157 subs | 1 h 44 min627 subs | 6 h 58 min2,506 subs |
| Bortle 5Suburban | 29 min174 subs | 1 h 55 min693 subs | 7 h 42 min2,770 subs |
| Bortle 6Bright suburban | 36 min214 subs | 2 h 22 min855 subs | 9 h 29 min3,417 subs |
| Bortle 7Suburban / urban transition | 48 min291 subs | 3 h 14 min1,163 subs | 13 h4,651 subs |
| Bortle 8City | 1 h 08 min411 subs | 4 h 34 min1,642 subs | 18 h6,567 subs |
| Bortle 9Inner city | 1 h 51 min666 subs | 7 h 24 min2,664 subs | 30 h10,654 subs |
Power and kit for this session
Allowing for slewing, focusing and rejected subs, that is about 3 h 05 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 Tulip Nebula is 16′ × 9′ across. The Seestar S50 frames 1.28° × 0.72° at 2.39″ per pixel, so it fills 37% of the frame’s short side.
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 | 1 h 37 min585 subs | 1 h 55 min693 subs | 3 h 14 min1,163 subs |
| 20 s | 1 h 09 min209 subs | 1 h 27 min263 subs | 2 h 46 min498 subs |
| 30 s | 1 h121 subs | 1 h 18 min157 subs | 2 h 36 min313 subs |
| 60 s | 51 min51 subs | 1 h 09 min69 subs | 2 h 27 min148 subs |
With and without the dual-band filter
| Filter | Bortle 3 | Bortle 5 | Bortle 7 |
|---|---|---|---|
| UV/IR-cut (no light-pollution filter) | 1 h 25 min508 subs | 2 h 23 min859 subs | 6 h 39 min2,396 subs |
| dual-band (LP filter) | 1 h 37 min585 subs | 1 h 55 min693 subs | 3 h 14 min1,163 subs |
About the Tulip Nebula
A compact hydrogen bloom in Cygnus near the black hole Cygnus X-1. Small and moderately faint; dual-band.
Sh2-101 · Emission nebula in Cygnus · magnitude 9.0 · 16′ × 9′ · 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 Tulip 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
- Tulip Nebula with the ZWO Seestar S50 Pro: 2 h 40 min from Bortle 6
- Tulip Nebula with the ZWO Seestar S30: 2 h 47 min from Bortle 6
- Tulip Nebula with the ZWO Seestar S30 Pro: 2 h 53 min from Bortle 6
- Tulip Nebula with the DwarfLab DWARF 3: 2 h 55 min from Bortle 6
- Tulip Nebula with the DwarfLab DWARF mini: 2 h 20 min from Bortle 6
- Tulip Nebula with the DwarfLab Draco: 1 h 52 min from Bortle 6
- Tulip Nebula with the DwarfLab DWARF II: 13 h from Bortle 6
- Tulip Nebula with the Vaonis Vespera II: 3 h 51 min from Bortle 6
- Tulip Nebula with the Vaonis Vespera Pro: 8 h 39 min from Bortle 6
- Tulip Nebula with the Vaonis Vespera 3: 3 h 41 min from Bortle 6
- Tulip Nebula with the Vaonis Vespera Pro 2: 8 h 15 min from Bortle 6
- Tulip Nebula with the Unistellar eQuinox 2: 3 h 32 min from Bortle 6
- Tulip Nebula with the Unistellar Odyssey: 16 h from Bortle 6
- Tulip Nebula with the Celestron Origin: 1 h 01 min from Bortle 6
- Tulip Nebula with the Celestron Origin Mark II: 1 h 24 min from Bortle 6
All telescopes for the Tulip Nebula · All targets for the Seestar S50