How long to image the Helix Nebula with the ZWO Seestar S30
From a Bortle 6 suburban sky, the ZWO Seestar S30 needs about 2 h 20 min (843 subs of 10 s with the built-in dual-band (LP filter) filter) for a solid image of the Helix Nebula. A quick look takes 35 min; a showpiece 9 h 22 min. Under a Bortle 3 rural sky the solid figure drops to 1 h 43 min. At Bortle 6 the limit is a mix of skyglow and read noise. In this scope's field it fills 35% 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 | 25 min150 subs | 1 h 39 min597 subs | 6 h 38 min2,386 subs |
| Bortle 2Typical dark site | 25 min151 subs | 1 h 41 min604 subs | 6 h 43 min2,416 subs |
| Bortle 3Rural | 26 min155 subs | 1 h 43 min619 subs | 6 h 52 min2,473 subs |
| Bortle 4Rural / suburban transition | 27 min164 subs | 1 h 49 min653 subs | 7 h 15 min2,612 subs |
| Bortle 5Suburban | 29 min177 subs | 1 h 58 min708 subs | 7 h 52 min2,831 subs |
| Bortle 6Bright suburban | 35 min211 subs | 2 h 20 min843 subs | 9 h 22 min3,370 subs |
| Bortle 7Suburban / urban transition | 46 min275 subs | 3 h 03 min1,099 subs | 12 h4,396 subs |
| Bortle 8City | 1 h 02 min375 subs | 4 h 10 min1,498 subs | 17 h5,990 subs |
| Bortle 9Inner city | 1 h 38 min587 subs | 6 h 31 min2,348 subs | 26 h9,389 subs |
Power and kit for this session
Allowing for slewing, focusing and rejected subs, that is about 3 h 03 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 Helix Nebula is 25′ × 22′ across. The Seestar S30 frames 2.13° × 1.20° at 3.99″ per pixel, so it fills 35% 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 43 min619 subs | 1 h 58 min708 subs | 3 h 03 min1,099 subs |
| 20 s | 1 h 09 min209 subs | 1 h 24 min254 subs | 2 h 30 min449 subs |
| 30 s | 58 min117 subs | 1 h 13 min147 subs | 2 h 18 min277 subs |
| 60 s | 47 min48 subs | 1 h 02 min63 subs | 2 h 07 min128 subs |
With and without the dual-band filter
| Filter | Bortle 3 | Bortle 5 | Bortle 7 |
|---|---|---|---|
| UV/IR-cut (no light-pollution filter) | 1 h 21 min489 subs | 2 h 10 min781 subs | 5 h 43 min2,060 subs |
| dual-band (LP filter) | 1 h 43 min619 subs | 1 h 58 min708 subs | 3 h 03 min1,099 subs |
About the Helix Nebula
The nearest bright planetary nebula, half the Moon's width but spread thin. Low from the UK; dual-band and a couple of hours make the eye appear.
NGC 7293, Caldwell 63 · Planetary nebula in Aquarius · magnitude 7.3 · 25′ × 22′ · best in Aug, Sep, Oct. Reachable from mid-northern latitudes (UK, northern US, central Europe) and from the south.
Planetary nebulae are small but intensely bright per pixel in OIII and H-alpha, so they respond very well to a dual-band filter and do not need much time for the main shell. The faint outer halos most of them have are a different proposition and need hours. Keep subs short if the central region saturates.
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 Helix 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
- Helix Nebula with the ZWO Seestar S50: 2 h from Bortle 6
- Helix Nebula with the ZWO Seestar S50 Pro: 2 h 15 min from Bortle 6
- Helix Nebula with the ZWO Seestar S30 Pro: 2 h 25 min from Bortle 6
- Helix Nebula with the DwarfLab DWARF 3: 2 h 28 min from Bortle 6
- Helix Nebula with the DwarfLab DWARF mini: 1 h 58 min from Bortle 6
- Helix Nebula with the DwarfLab Draco: 1 h 35 min from Bortle 6
- Helix Nebula with the DwarfLab DWARF II: 11 h from Bortle 6
- Helix Nebula with the Vaonis Vespera II: 3 h 13 min from Bortle 6
- Helix Nebula with the Vaonis Vespera Pro: 7 h 14 min from Bortle 6
- Helix Nebula with the Vaonis Vespera 3: 3 h 05 min from Bortle 6
- Helix Nebula with the Vaonis Vespera Pro 2: 6 h 53 min from Bortle 6
- Helix Nebula with the Unistellar eQuinox 2: 2 h 57 min from Bortle 6
- Helix Nebula with the Unistellar Odyssey: 14 h from Bortle 6
- Helix Nebula with the Celestron Origin: 51 min from Bortle 6
- Helix Nebula with the Celestron Origin Mark II: 1 h 10 min from Bortle 6
All telescopes for the Helix Nebula · All targets for the Seestar S30