How long to image the Lagoon Nebula with the DwarfLab Draco
From a Bortle 6 suburban sky, the DwarfLab Draco needs about 16 min (32 subs of 30 s with the built-in dual-narrowband (Hα + OIII) filter) for a solid image of the Lagoon Nebula. A quick look takes 5 min; a showpiece 1 h 03 min. Under a Bortle 3 rural sky the solid figure drops to 15 min. At Bortle 6 the limit is a mix of skyglow and read noise. In this scope's field it is just over the frame at 1.2×.
| Sky | Quick lookTarget obvious, still noisy | SolidClean enough to share | ShowpieceSmooth faint detail, print-worthy |
|---|---|---|---|
| Bortle 1Excellent dark site | 5 min10 subs | 15 min30 subs | 45 min90 subs |
| Bortle 2Typical dark site | 5 min10 subs | 15 min30 subs | 45 min91 subs |
| Bortle 3Rural | 5 min10 subs | 15 min30 subs | 46 min93 subs |
| Bortle 4Rural / suburban transition | 5 min10 subs | 15 min30 subs | 49 min98 subs |
| Bortle 5Suburban | 5 min10 subs | 15 min30 subs | 53 min106 subs |
| Bortle 6Bright suburban | 5 min10 subs | 16 min32 subs | 1 h 03 min126 subs |
| Bortle 7Suburban / urban transition | 5 min11 subs | 20 min41 subs | 1 h 22 min164 subs |
| Bortle 8City | 7 min14 subs | 28 min56 subs | 1 h 51 min222 subs |
| Bortle 9Inner city | 11 min22 subs | 43 min87 subs | 2 h 53 min347 subs |
Power and kit for this session
Allowing for slewing, focusing and rejected subs, that is about 20 min of run time. The Draco’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 PD power bank 20000mAhRated 5 h on its 10,000 mAh battery. DwarfLab has not published the charging input, so check PD support before relying on it mid-session.
- 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 Lagoon Nebula is 90′ × 40′ across. The Draco frames 1.66° × 1.24° at 1.46″ per pixel, so it is just over the frame at 1.2×. Point at the part you want; the edges will fall outside the frame.
Longer subs
Auto Mode picks the exposure; Pro Mode allows up to 300 s, held by built-in guiding and field derotation. The 30 s default here is our assumption. Time for a solid image by sub length:
| Sub length | Bortle 3 | Bortle 5 | Bortle 7 |
|---|---|---|---|
| 30 s | 15 min30 subs | 15 min30 subs | 20 min41 subs |
| 60 s | 30 min30 subs | 30 min30 subs | 30 min30 subs |
| 120 s | 1 h30 subs | 1 h30 subs | 1 h30 subs |
| 300 s | 2 h 30 min30 subs | 2 h 30 min30 subs | 2 h 30 min30 subs |
With and without the dual-band filter
| Filter | Bortle 3 | Bortle 5 | Bortle 7 |
|---|---|---|---|
| No filter | 15 min30 subs | 15 min31 subs | 39 min78 subs |
| dual-narrowband (Hα + OIII) | 15 min30 subs | 15 min30 subs | 20 min41 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 Draco
DwarfLab’s big scope: 90 mm of folded f/3.8 optics, the most aperture of any Seestar or DWARF, a narrow 13 nm dual-band filter and 300 s subs with built-in guiding. A small-target scope; big nebulae need its mosaic mode.
Auto Mode picks the exposure; Pro Mode allows up to 300 s, held by built-in guiding and field derotation. The 30 s default here is our assumption. Built-in Hα + OIII dual-narrowband filter, 13 nm per line; the SHO Edition adds an SII option.
Longer subs matter most under dark skies, where read noise rather than skyglow sets the floor. From a city the difference between 30 s and 300 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 Draco? 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 3: 25 min from Bortle 6
- Lagoon Nebula with the DwarfLab DWARF mini: 19 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 Draco