How long to image the Lagoon Nebula with the DwarfLab DWARF 3
From a Bortle 6 suburban sky, the DwarfLab DWARF 3 needs about 25 min (102 subs of 15 s with the built-in dual-band filter) for a solid image of the Lagoon Nebula. A quick look takes 6 min; a showpiece 1 h 42 min. Under a Bortle 3 rural sky the solid figure drops to 18 min. At Bortle 6 the limit is a mix of skyglow and read noise. In this scope's field it only just fits, at 91% of the short side.
| Sky | Quick lookTarget obvious, still noisy | SolidClean enough to share | ShowpieceSmooth faint detail, print-worthy |
|---|---|---|---|
| Bortle 1Excellent dark site | 4 min18 subs | 17 min69 subs | 1 h 08 min274 subs |
| Bortle 2Typical dark site | 4 min18 subs | 17 min70 subs | 1 h 09 min278 subs |
| Bortle 3Rural | 4 min18 subs | 18 min72 subs | 1 h 11 min286 subs |
| Bortle 4Rural / suburban transition | 5 min20 subs | 19 min77 subs | 1 h 16 min305 subs |
| Bortle 5Suburban | 5 min21 subs | 21 min84 subs | 1 h 24 min335 subs |
| Bortle 6Bright suburban | 6 min26 subs | 25 min102 subs | 1 h 42 min408 subs |
| Bortle 7Suburban / urban transition | 9 min35 subs | 34 min137 subs | 2 h 17 min547 subs |
| Bortle 8City | 12 min48 subs | 48 min191 subs | 3 h 11 min763 subs |
| Bortle 9Inner city | 19 min77 subs | 1 h 17 min307 subs | 5 h 06 min1,225 subs |
Power and kit for this session
Allowing for slewing, focusing and rejected subs, that is about 33 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 Lagoon Nebula is 90′ × 40′ across. The DWARF 3 frames 2.93° × 1.65° at 2.75″ per pixel, so it only just fits, at 91% of the short side. Centre it carefully: there is no room to crop back afterwards.
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 | 18 min72 subs | 21 min84 subs | 34 min137 subs |
| 30 s | 16 min33 subs | 19 min39 subs | 32 min65 subs |
| 60 s | 30 min30 subs | 30 min30 subs | 32 min32 subs |
With and without the dual-band filter
| Filter | Bortle 3 | Bortle 5 | Bortle 7 |
|---|---|---|---|
| Astro (no light-pollution filter) | 16 min66 subs | 26 min105 subs | 1 h 10 min279 subs |
| dual-band | 18 min72 subs | 21 min84 subs | 34 min137 subs |
About the Lagoon Nebula
The showpiece emission nebula of the summer Milky Way, bright enough to catch its core in minutes. Pair it with the Trifid in one wide frame.
M8, NGC 6523 · Emission nebula in Sagittarius · magnitude 6.0 · 90′ × 40′ · 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 Lagoon 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
- Lagoon Nebula with the ZWO Seestar S50: 20 min from Bortle 6
- Lagoon Nebula with the ZWO Seestar S50 Pro: 22 min from Bortle 6
- Lagoon Nebula with the ZWO Seestar S30: 22 min from Bortle 6
- Lagoon Nebula with the ZWO Seestar S30 Pro: 24 min from Bortle 6
- Lagoon Nebula with the DwarfLab DWARF mini: 19 min from Bortle 6
- Lagoon Nebula with the DwarfLab Draco: 16 min from Bortle 6
- Lagoon Nebula with the DwarfLab DWARF II: 1 h 35 min from Bortle 6
- Lagoon Nebula with the Vaonis Vespera II: 28 min from Bortle 6
- Lagoon Nebula with the Vaonis Vespera Pro: 1 h 03 min from Bortle 6
- Lagoon Nebula with the Vaonis Vespera 3: 27 min from Bortle 6
- Lagoon Nebula with the Vaonis Vespera Pro 2: 1 h from Bortle 6
- Lagoon Nebula with the Unistellar eQuinox 2: 25 min from Bortle 6
- Lagoon Nebula with the Unistellar Odyssey: 1 h 55 min from Bortle 6
- Lagoon Nebula with the Celestron Origin: 7 min from Bortle 6
- Lagoon Nebula with the Celestron Origin Mark II: 10 min from Bortle 6
All telescopes for the Lagoon Nebula · All targets for the DWARF 3