How long to image the Omega Nebula with the DwarfLab DWARF 3
From a Bortle 6 suburban sky, the DwarfLab DWARF 3 needs about 30 min (120 subs of 15 s with the built-in dual-band filter) for a solid image of the Omega Nebula. A quick look takes 7 min; a showpiece 2 h. 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 11% 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 min21 subs | 20 min82 subs | 1 h 22 min327 subs |
| Bortle 2Typical dark site | 5 min21 subs | 21 min83 subs | 1 h 23 min332 subs |
| Bortle 3Rural | 5 min22 subs | 21 min86 subs | 1 h 25 min341 subs |
| Bortle 4Rural / suburban transition | 6 min23 subs | 23 min91 subs | 1 h 30 min362 subs |
| Bortle 5Suburban | 6 min25 subs | 25 min99 subs | 1 h 39 min396 subs |
| Bortle 6Bright suburban | 7 min30 subs | 30 min120 subs | 2 h479 subs |
| Bortle 7Suburban / urban transition | 10 min40 subs | 40 min160 subs | 2 h 39 min637 subs |
| Bortle 8City | 14 min56 subs | 55 min221 subs | 3 h 40 min882 subs |
| Bortle 9Inner city | 22 min88 subs | 1 h 28 min352 subs | 5 h 51 min1,406 subs |
Power and kit for this session
Allowing for slewing, focusing and rejected subs, that is about 39 min of run time. The DWARF 3’s battery (rated about 5 h 30 min) 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 18W18 W PD input and it runs while charging; needs a C-to-C cable for PD.
- 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 DWARF 3 →
How it frames
The Omega Nebula is 11′ across. The DWARF 3 frames 2.93° × 1.65° at 2.75″ per pixel, so it fills 11% of the frame’s short side.
Longer subs
Auto mode caps subs at 15 s; 30 s and longer need EQ mode, and 60 s is the ceiling on the tele camera. Time for a solid image by sub length:
| Sub length | Bortle 3 | Bortle 5 | Bortle 7 |
|---|---|---|---|
| 15 s | 21 min86 subs | 25 min99 subs | 40 min160 subs |
| 30 s | 19 min39 subs | 23 min46 subs | 38 min76 subs |
| 60 s | 30 min30 subs | 30 min30 subs | 37 min37 subs |
With and without the dual-band filter
| Filter | Bortle 3 | Bortle 5 | Bortle 7 |
|---|---|---|---|
| Astro (no light-pollution filter) | 19 min77 subs | 30 min122 subs | 1 h 20 min319 subs |
| dual-band | 21 min86 subs | 25 min99 subs | 40 min160 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 DwarfLab DWARF 3
Small pixels on a 35 mm f/4.3 lens give a sharper image than its aperture suggests, and EQ mode with 60 s subs makes it the read-noise winner in dark skies.
Auto mode caps subs at 15 s; 30 s and longer need EQ mode, and 60 s is the ceiling on the tele camera. Three built-in filters: VIS, Astro (430 to 690 nm) and dual-band Hα 656 nm / OIII 501 nm.
Longer subs matter most under dark skies, where read noise rather than skyglow sets the floor. From a city the difference between 15 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 DWARF 3? 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 ZWO Seestar S30 Pro: 27 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 DWARF 3