How long to image the Pacman Nebula with the ZWO Seestar S30
From a Bortle 6 suburban sky, the ZWO Seestar S30 needs about 1 h 58 min (709 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 30 min; a showpiece 7 h 52 min. Under a Bortle 3 rural sky the solid figure drops to 1 h 27 min. At Bortle 6 the limit is a mix of skyglow and read noise. In this scope's field it fills 49% 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 | 21 min127 subs | 1 h 24 min505 subs | 5 h 36 min2,017 subs |
| Bortle 2Typical dark site | 21 min128 subs | 1 h 25 min511 subs | 5 h 40 min2,042 subs |
| Bortle 3Rural | 22 min131 subs | 1 h 27 min523 subs | 5 h 48 min2,089 subs |
| Bortle 4Rural / suburban transition | 23 min138 subs | 1 h 32 min551 subs | 6 h 07 min2,204 subs |
| Bortle 5Suburban | 25 min150 subs | 1 h 39 min597 subs | 6 h 38 min2,387 subs |
| Bortle 6Bright suburban | 30 min178 subs | 1 h 58 min709 subs | 7 h 52 min2,835 subs |
| Bortle 7Suburban / urban transition | 38 min231 subs | 2 h 34 min923 subs | 10 h3,689 subs |
| Bortle 8City | 52 min314 subs | 3 h 29 min1,254 subs | 14 h5,015 subs |
| Bortle 9Inner city | 1 h 22 min491 subs | 5 h 27 min1,961 subs | 22 h7,842 subs |
Power and kit for this session
Allowing for slewing, focusing and rejected subs, that is about 2 h 34 min of run time. The Seestar S30’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 10000mAh 5V 3A6,000 mAh inside; a 10,000 mAh 5 V 3 A bank roughly doubles a session.
- Seestar S30 dew shieldHeater is built in; a cheap shield reduces dew and 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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How it frames
The Pacman Nebula is 35′ × 30′ across. The Seestar S30 frames 2.13° × 1.20° at 3.99″ per pixel, so it fills 49% of the frame’s short side.
Longer subs
10, 20 and 30 s in Alt-Az; 60 s only in EQ mode, which needs the TH10 head. Time for a solid image by sub length:
| Sub length | Bortle 3 | Bortle 5 | Bortle 7 |
|---|---|---|---|
| 10 s | 1 h 27 min523 subs | 1 h 39 min597 subs | 2 h 34 min923 subs |
| 20 s | 59 min178 subs | 1 h 12 min215 subs | 2 h 06 min378 subs |
| 30 s | 50 min100 subs | 1 h 02 min125 subs | 1 h 56 min233 subs |
| 60 s | 41 min41 subs | 53 min53 subs | 1 h 47 min108 subs |
With and without the dual-band filter
| Filter | Bortle 3 | Bortle 5 | Bortle 7 |
|---|---|---|---|
| UV/IR-cut (no light-pollution filter) | 1 h 09 min412 subs | 1 h 49 min656 subs | 4 h 46 min1,719 subs |
| dual-band (LP filter) | 1 h 27 min523 subs | 1 h 39 min597 subs | 2 h 34 min923 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 S30
Wider and lighter than the S50 with the same 2.9 µm pixels, so its per-pixel speed on extended targets is close despite the smaller aperture. Ideal for big nebulae.
10, 20 and 30 s in Alt-Az; 60 s only in EQ mode, which needs the TH10 head. Built-in UV/IR-cut, dual-band (OIII 30 nm / Hα 20 nm) and dark filters.
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 S30? 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 S50 Pro: 1 h 53 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 S30