How long to image the Omega Nebula with the ZWO Seestar S30 Pro
From a Bortle 6 suburban sky, the ZWO Seestar S30 Pro needs about 27 min (165 subs of 10 s with the built-in dual-band (LP filter) filter) for a solid image of the Omega Nebula. A quick look takes 7 min; a showpiece 1 h 50 min. Under a Bortle 3 rural sky the solid figure drops to 21 min. At Bortle 6 the limit is a mix of skyglow and read noise. In this scope's field it fills 8% 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 | 5 min31 subs | 20 min123 subs | 1 h 22 min492 subs |
| Bortle 2Typical dark site | 5 min32 subs | 21 min125 subs | 1 h 23 min497 subs |
| Bortle 3Rural | 5 min32 subs | 21 min127 subs | 1 h 24 min507 subs |
| Bortle 4Rural / suburban transition | 6 min34 subs | 22 min133 subs | 1 h 28 min530 subs |
| Bortle 5Suburban | 6 min36 subs | 24 min142 subs | 1 h 35 min568 subs |
| Bortle 6Bright suburban | 7 min42 subs | 27 min165 subs | 1 h 50 min659 subs |
| Bortle 7Suburban / urban transition | 9 min53 subs | 35 min209 subs | 2 h 19 min834 subs |
| Bortle 8City | 12 min70 subs | 46 min277 subs | 3 h 04 min1,105 subs |
| Bortle 9Inner city | 18 min106 subs | 1 h 10 min421 subs | 4 h 40 min1,683 subs |
Power and kit for this session
Allowing for slewing, focusing and rejected subs, that is about 36 min of run time. The Seestar S30 Pro’s battery (rated about 5 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 3A5 V 3 A input and it runs while charging.
- Seestar S30 Pro dew shieldActive anti-dew is built in; a shield adds margin. The S30 Pro front differs from the S30, so check the listing.
- 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 S30 Pro →
How it frames
The Omega Nebula is 11′ across. The Seestar S30 Pro frames 3.99° × 2.24° at 3.74″ per pixel, so it fills 8% 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 | 21 min127 subs | 24 min142 subs | 35 min209 subs |
| 20 s | 17 min50 subs | 19 min58 subs | 30 min91 subs |
| 30 s | 15 min31 subs | 18 min36 subs | 29 min58 subs |
| 60 s | 30 min30 subs | 30 min30 subs | 30 min30 subs |
With and without the dual-band filter
| Filter | Bortle 3 | Bortle 5 | Bortle 7 |
|---|---|---|---|
| UV/IR-cut (no light-pollution filter) | 17 min101 subs | 25 min151 subs | 1 h 01 min369 subs |
| dual-band (LP filter) | 21 min127 subs | 24 min142 subs | 35 min209 subs |
About the Omega Nebula
A bright, compact swan-shaped emission nebula, one of the brightest in the sky per unit area. Excellent from suburban skies.
M17, NGC 6618, Swan Nebula · Emission nebula in Sagittarius · magnitude 6.0 · 11′ · best in Jun, Jul, Aug. 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 Pro
The S30 optics upgraded to a quadruplet in front of an 8 MP IMX585. Same speed per pixel as the S30, four times the pixels, so you can crop hard.
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 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 Omega Nebula from a Seestar S30 Pro? Email it with your total time and sky to [email protected] and it goes here, credited.
Same target, other telescopes
- Omega Nebula with the ZWO Seestar S50: 23 min from Bortle 6
- Omega Nebula with the ZWO Seestar S50 Pro: 26 min from Bortle 6
- Omega Nebula with the ZWO Seestar S30: 26 min from Bortle 6
- Omega Nebula with the DwarfLab DWARF 3: 30 min from Bortle 6
- Omega Nebula with the DwarfLab DWARF mini: 23 min from Bortle 6
- Omega Nebula with the DwarfLab Draco: 18 min from Bortle 6
- Omega Nebula with the DwarfLab DWARF II: 1 h 49 min from Bortle 6
- Omega Nebula with the Vaonis Vespera II: 32 min from Bortle 6
- Omega Nebula with the Vaonis Vespera Pro: 1 h 12 min from Bortle 6
- Omega Nebula with the Vaonis Vespera 3: 31 min from Bortle 6
- Omega Nebula with the Vaonis Vespera Pro 2: 1 h 09 min from Bortle 6
- Omega Nebula with the Unistellar eQuinox 2: 29 min from Bortle 6
- Omega Nebula with the Unistellar Odyssey: 2 h 11 min from Bortle 6
- Omega Nebula with the Celestron Origin: 9 min from Bortle 6
- Omega Nebula with the Celestron Origin Mark II: 12 min from Bortle 6
All telescopes for the Omega Nebula · All targets for the Seestar S30 Pro