How long to image the Lagoon Nebula with the DwarfLab DWARF mini

From a Bortle 6 suburban sky, the DwarfLab DWARF mini needs about 19 min (78 subs of 15 s with the built-in dual-band filter) for a solid image of the Lagoon Nebula. A quick look takes 5 min; a showpiece 1 h 18 min. Under a Bortle 3 rural sky the solid figure drops to 14 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 1.3×.

Lagoon Nebula with the DwarfLab DWARF mini: 15 s subs with the built-in dual-band filter.
SkyQuick lookTarget obvious, still noisySolidClean enough to shareShowpieceSmooth faint detail, print-worthy
Bortle 1Excellent dark site4 min15 subs14 min57 subs56 min225 subs
Bortle 2Typical dark site4 min15 subs14 min57 subs57 min227 subs
Bortle 3Rural4 min15 subs14 min58 subs58 min232 subs
Bortle 4Rural / suburban transition4 min16 subs15 min62 subs1 h 01 min245 subs
Bortle 5Suburban4 min17 subs16 min66 subs1 h 06 min264 subs
Bortle 6Bright suburban5 min20 subs19 min78 subs1 h 18 min311 subs
Bortle 7Suburban / urban transition6 min26 subs25 min101 subs1 h 40 min402 subs
Bortle 8City8 min34 subs34 min136 subs2 h 15 min542 subs
Bortle 9Inner city13 min53 subs52 min210 subs3 h 30 min840 subs

Adjust in the calculator

Power and kit for this session

Allowing for slewing, focusing and rejected subs, that is about 25 min of run time. The DWARF mini’s battery (rated about 3 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.)

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How it frames

The Lagoon Nebula is 90′ × 40′ across. The DWARF mini frames 2.13° × 1.20° at 3.99″ per pixel, so it is just over the frame at 1.3×. Point at the part you want; the edges will fall outside the frame.

Longer subs

Auto mode caps subs at 15 s; 30 s and longer need EQ mode, and 90 s is the ceiling. Time for a solid image by sub length:

Sub lengthBortle 3Bortle 5Bortle 7
15 s14 min58 subs16 min66 subs25 min101 subs
30 s15 min30 subs15 min30 subs22 min45 subs
60 s30 min30 subs30 min30 subs30 min30 subs
90 s45 min30 subs45 min30 subs45 min30 subs

With and without the dual-band filter

Solid quality, default sub length.
FilterBortle 3Bortle 5Bortle 7
Astro (no light-pollution filter)12 min48 subs18 min74 subs47 min187 subs
dual-band14 min58 subs16 min66 subs25 min101 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 mini

DwarfLab’s answer to the Seestar S30: same sensor and focal length, big pixels, dual-band filter built in, and 90 s subs in EQ mode. Sensitivity over megapixels.

Auto mode caps subs at 15 s; 30 s and longer need EQ mode, and 90 s is the ceiling. Built-in Astro (430 to 690 nm), dark-frame and dual-band Hα / OIII filters; no plain VIS filter on the tele camera.

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 90 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.

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Imaged the Lagoon Nebula with your DWARF mini? Did the solid figure match?Anonymous, one tap. It is how the model gets calibrated.

Have an image of the Lagoon Nebula from a DWARF mini? Email it with your total time and sky to [email protected] and it goes here, credited.

Same target, other telescopes

All telescopes for the Lagoon Nebula · All targets for the DWARF mini