How long to image the Soul Nebula with the ZWO Seestar S50
From a Bortle 6 suburban sky, the ZWO Seestar S50 needs about 3 h 21 min (1,208 subs of 10 s with the built-in dual-band (LP filter) filter) for a solid image of the Soul Nebula. A quick look takes 50 min; a showpiece 13 h. Under a Bortle 3 rural sky the solid figure drops to 2 h 16 min. At Bortle 6 the limit is a mix of skyglow and read noise. In this scope's field it is just over the frame at 1.4×.
| Sky | Quick lookTarget obvious, still noisy | SolidClean enough to share | ShowpieceSmooth faint detail, print-worthy |
|---|---|---|---|
| Bortle 1Excellent dark site | 33 min196 subs | 2 h 10 min781 subs | 8 h 40 min3,122 subs |
| Bortle 2Typical dark site | 33 min199 subs | 2 h 12 min794 subs | 8 h 49 min3,174 subs |
| Bortle 3Rural | 34 min205 subs | 2 h 16 min819 subs | 9 h 06 min3,274 subs |
| Bortle 4Rural / suburban transition | 37 min220 subs | 2 h 26 min879 subs | 9 h 46 min3,514 subs |
| Bortle 5Suburban | 41 min244 subs | 2 h 42 min974 subs | 11 h3,896 subs |
| Bortle 6Bright suburban | 50 min302 subs | 3 h 21 min1,208 subs | 13 h4,832 subs |
| Bortle 7Suburban / urban transition | 1 h 09 min414 subs | 4 h 36 min1,654 subs | 18 h6,616 subs |
| Bortle 8City | 1 h 38 min587 subs | 6 h 31 min2,347 subs | 26 h9,386 subs |
| Bortle 9Inner city | 2 h 39 min956 subs | 11 h3,824 subs | 42 h15,293 subs |
Power and kit for this session
Allowing for slewing, focusing and rejected subs, that is about 4 h 22 min of run time. The Seestar S50’s battery is rated at about 6 h, less near freezing, so the session needs an external power bank. (Bortle 6, solid image; we allow 30% over the integration time, and 30% off the battery for a November night.)
- 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.
- hand warmers long lastingAir-activated packs give hours of heat for the person; winter nights are long and you spend most of them standing still.
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Everything that fits the Seestar S50 →
How it frames
The Soul Nebula is 60′ × 30′ across. The Seestar S50 frames 1.28° × 0.72° at 2.39″ per pixel, so it is just over the frame at 1.4×. 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 (app 2.5 and later). Time for a solid image by sub length:
| Sub length | Bortle 3 | Bortle 5 | Bortle 7 |
|---|---|---|---|
| 10 s | 2 h 16 min819 subs | 2 h 42 min974 subs | 4 h 36 min1,654 subs |
| 20 s | 1 h 36 min288 subs | 2 h 02 min366 subs | 3 h 55 min706 subs |
| 30 s | 1 h 22 min165 subs | 1 h 48 min217 subs | 3 h 42 min444 subs |
| 60 s | 1 h 09 min69 subs | 1 h 35 min95 subs | 3 h 28 min209 subs |
With and without the dual-band filter
| Filter | Bortle 3 | Bortle 5 | Bortle 7 |
|---|---|---|---|
| UV/IR-cut (no light-pollution filter) | 1 h 59 min715 subs | 3 h 24 min1,223 subs | 9 h 34 min3,445 subs |
| dual-band (LP filter) | 2 h 16 min819 subs | 2 h 42 min974 subs | 4 h 36 min1,654 subs |
About the Soul Nebula
The Heart's companion, a knobbly emission cloud full of pillars. Faint overall; long dual-band integrations reward you.
IC 1848, Sh2-199 · Emission nebula in Cassiopeia · magnitude 6.5 · 60′ × 30′ · best in Oct, Nov, Dec. 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 Soul 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
- Soul Nebula with the ZWO Seestar S50 Pro: 3 h 46 min from Bortle 6
- Soul Nebula with the ZWO Seestar S30: 3 h 57 min from Bortle 6
- Soul Nebula with the ZWO Seestar S30 Pro: 4 h 04 min from Bortle 6
- Soul Nebula with the DwarfLab DWARF 3: 4 h 06 min from Bortle 6
- Soul Nebula with the DwarfLab DWARF mini: 3 h 18 min from Bortle 6
- Soul Nebula with the DwarfLab Draco: 2 h 39 min from Bortle 6
- Soul Nebula with the DwarfLab DWARF II: 19 h from Bortle 6
- Soul Nebula with the Vaonis Vespera II: 5 h 31 min from Bortle 6
- Soul Nebula with the Vaonis Vespera Pro: 12 h from Bortle 6
- Soul Nebula with the Vaonis Vespera 3: 5 h 16 min from Bortle 6
- Soul Nebula with the Vaonis Vespera Pro 2: 12 h from Bortle 6
- Soul Nebula with the Unistellar eQuinox 2: 5 h 05 min from Bortle 6
- Soul Nebula with the Unistellar Odyssey: 24 h from Bortle 6
- Soul Nebula with the Celestron Origin: 1 h 27 min from Bortle 6
- Soul Nebula with the Celestron Origin Mark II: 2 h from Bortle 6
All telescopes for the Soul Nebula · All targets for the Seestar S50