How long to image the Pacman Nebula with the ZWO Seestar S50 Pro
From a Bortle 6 suburban sky, the ZWO Seestar S50 Pro needs about 1 h 53 min (681 subs of 10 s with the built-in dual-band (LP filter) filter) for a solid image of the Pacman Nebula. A quick look takes 28 min; a showpiece 7 h 34 min. Under a Bortle 3 rural sky the solid figure drops to 1 h 20 min. At Bortle 6 the limit is a mix of skyglow and read noise. In this scope's field it fills 42% 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 | 19 min115 subs | 1 h 17 min460 subs | 5 h 06 min1,837 subs |
| Bortle 2Typical dark site | 19 min117 subs | 1 h 18 min466 subs | 5 h 11 min1,864 subs |
| Bortle 3Rural | 20 min120 subs | 1 h 20 min479 subs | 5 h 19 min1,915 subs |
| Bortle 4Rural / suburban transition | 21 min128 subs | 1 h 25 min510 subs | 5 h 40 min2,040 subs |
| Bortle 5Suburban | 23 min140 subs | 1 h 33 min560 subs | 6 h 13 min2,238 subs |
| Bortle 6Bright suburban | 28 min171 subs | 1 h 53 min681 subs | 7 h 34 min2,722 subs |
| Bortle 7Suburban / urban transition | 38 min228 subs | 2 h 32 min912 subs | 10 h3,646 subs |
| Bortle 8City | 53 min318 subs | 3 h 32 min1,270 subs | 14 h5,080 subs |
| Bortle 9Inner city | 1 h 25 min509 subs | 5 h 39 min2,035 subs | 23 h8,138 subs |
Power and kit for this session
Allowing for slewing, focusing and rejected subs, that is about 2 h 27 min of run time. The Seestar S50 Pro’s battery (rated about 9 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 PD power bank 20000mAh 30WAccepts 12 V 3 A PD, so a 30 W bank tops up the 10,000 mAh cell while imaging.
- Seestar S50 Pro dew shieldDew heater is built in; a shield adds margin on damp nights. Check the listing says S50 Pro.
- 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 Pro →
How it frames
The Pacman Nebula is 35′ × 30′ across. The Seestar S50 Pro frames 2.45° × 1.38° at 2.30″ per pixel, so it fills 42% of the frame’s short side.
Longer subs
10, 20 and 30 s in Alt-Az; 60 s only in EQ mode, and 60 s is the ceiling. Time for a solid image by sub length:
| Sub length | Bortle 3 | Bortle 5 | Bortle 7 |
|---|---|---|---|
| 10 s | 1 h 20 min479 subs | 1 h 33 min560 subs | 2 h 32 min912 subs |
| 20 s | 57 min172 subs | 1 h 11 min212 subs | 2 h 09 min388 subs |
| 30 s | 50 min100 subs | 1 h 03 min126 subs | 2 h 02 min244 subs |
| 60 s | 42 min43 subs | 55 min56 subs | 1 h 54 min115 subs |
With and without the dual-band filter
| Filter | Bortle 3 | Bortle 5 | Bortle 7 |
|---|---|---|---|
| UV/IR-cut (no light-pollution filter) | 1 h 07 min404 subs | 1 h 51 min667 subs | 5 h 03 min1,817 subs |
| dual-band (LP filter) | 1 h 20 min479 subs | 1 h 33 min560 subs | 2 h 32 min912 subs |
About the Pacman Nebula
A bright emission nebula with a dark lane biting into it. Compact, bright, and excellent with a dual-band filter from suburban skies.
NGC 281 · Emission nebula in Cassiopeia · magnitude 7.4 · 35′ × 30′ · best in Sep, Oct, Nov. 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 Pro
The S50 optics at 260 mm on an 8 MP 1/1.2-inch sensor: a wider, taller field, four times the pixels, and 60 s subs in EQ mode. Per pixel it is a whisker slower than the S50 because of the longer focal length; the long subs make it the better dark-site scope.
10, 20 and 30 s in Alt-Az; 60 s only in EQ mode, and 60 s is the ceiling. 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 Pacman Nebula from a Seestar S50 Pro? Email it with your total time and sky to [email protected] and it goes here, credited.
Same target, other telescopes
- Pacman Nebula with the ZWO Seestar S50: 1 h 41 min from Bortle 6
- Pacman Nebula with the ZWO Seestar S30: 1 h 58 min from Bortle 6
- Pacman Nebula with the ZWO Seestar S30 Pro: 2 h 02 min from Bortle 6
- Pacman Nebula with the DwarfLab DWARF 3: 2 h 05 min from Bortle 6
- Pacman Nebula with the DwarfLab DWARF mini: 1 h 40 min from Bortle 6
- Pacman Nebula with the DwarfLab Draco: 1 h 20 min from Bortle 6
- Pacman Nebula with the DwarfLab DWARF II: 9 h 16 min from Bortle 6
- Pacman Nebula with the Vaonis Vespera II: 2 h 42 min from Bortle 6
- Pacman Nebula with the Vaonis Vespera Pro: 6 h 03 min from Bortle 6
- Pacman Nebula with the Vaonis Vespera 3: 2 h 35 min from Bortle 6
- Pacman Nebula with the Vaonis Vespera Pro 2: 5 h 46 min from Bortle 6
- Pacman Nebula with the Unistellar eQuinox 2: 2 h 28 min from Bortle 6
- Pacman Nebula with the Unistellar Odyssey: 11 h from Bortle 6
- Pacman Nebula with the Celestron Origin: 43 min from Bortle 6
- Pacman Nebula with the Celestron Origin Mark II: 59 min from Bortle 6
All telescopes for the Pacman Nebula · All targets for the Seestar S50 Pro