How long should I image the Lagoon Nebula with the Vespera Pro from a Bortle 6 sky?

About 1 h 03 min of total integration for a solid image, or 4 h 12 min for a showpiece. A quick look takes 16 min.

How many subs is that on the Vespera Pro?

At the default 10 s sub length, 378 subs for a solid image from Bortle 6 and 175 from Bortle 3.

Does a dual-band filter help on the Lagoon Nebula?

Yes. It is an emission-line object; from Bortle 6 the filter cuts the solid-image time from 1 h 03 min to 49 min.

How long to image the Lagoon Nebula with the Vaonis Vespera Pro

From a Bortle 6 suburban sky, the Vaonis Vespera Pro needs about 1 h 03 min (378 subs of 10 s) for a solid image of the Lagoon Nebula. A quick look takes 16 min; a showpiece 4 h 12 min. Under a Bortle 3 rural sky the solid figure drops to 29 min. At Bortle 6 the limit is skyglow, so a darker site or a filter helps more than longer subs. In this scope's field it only just fits, at 93% of the short side.

Lagoon Nebula with the Vaonis Vespera Pro: 10 s subs.
Sky	Quick lookTarget obvious, still noisy	SolidClean enough to share	ShowpieceSmooth faint detail, print-worthy
Bortle 1Excellent dark site	6 min39 subs	26 min155 subs	1 h 43 min619 subs
Bortle 2Typical dark site	7 min41 subs	27 min162 subs	1 h 48 min646 subs
Bortle 3Rural	7 min44 subs	29 min175 subs	1 h 56 min698 subs
Bortle 4Rural / suburban transition	9 min52 subs	34 min206 subs	2 h 17 min823 subs
Bortle 5Suburban	11 min64 subs	43 min256 subs	2 h 50 min1,022 subs
Bortle 6Bright suburban	16 min95 subs	1 h 03 min378 subs	4 h 12 min1,510 subs
Bortle 7Suburban / urban transition	25 min153 subs	1 h 42 min610 subs	6 h 46 min2,439 subs
Bortle 8City	40 min243 subs	2 h 42 min971 subs	11 h3,882 subs
Bortle 9Inner city	1 h 12 min435 subs	4 h 50 min1,740 subs	19 h6,960 subs

Adjust in the calculator

Power and kit for this session

Allowing for slewing, focusing and rejected subs, that is about 1 h 22 min of run time. The Vespera Pro’s battery (rated about 11 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 20000mAh 30WExtends the 11 h battery; 30 W PD per Vaonis.
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How it frames

The Lagoon Nebula is 90′ × 40′ across. The Vespera Pro frames 1.62° × 1.62° at 1.65″ per pixel, so it only just fits, at 93% of the short side. Centre it carefully: there is no room to crop back afterwards.

Longer subs

10 s subs by default; Expert Mode manual targets allow 1 to 30 s. Alt-azimuth only, no EQ mode. Time for a solid image by sub length:

Sub length	Bortle 3	Bortle 5	Bortle 7
10 s	29 min175 subs	43 min256 subs	1 h 42 min610 subs
20 s	25 min75 subs	38 min115 subs	1 h 37 min293 subs
30 s	23 min47 subs	37 min74 subs	1 h 36 min192 subs

With and without the dual-band filter

Solid quality, default sub length.
Filter	Bortle 3	Bortle 5	Bortle 7
No filter	29 min175 subs	43 min256 subs	1 h 42 min610 subs
dual-band (Dual Band filter), clip-on	38 min230 subs	42 min255 subs	1 h 01 min364 subs

The Vespera Pro has no built-in dual-band filter. Optional clip-on Vaonis filters: dual-band, light-pollution (CLS) and solar. On an emission target like this it is the single biggest upgrade you can make.

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 Vaonis Vespera Pro

The square-sensor Vespera with 2 µm pixels. Higher resolution than the II, and correspondingly slower per pixel: expect around double the time for the same per-pixel SNR. Run-out in 2026 and replaced by the Vespera Pro 2.

10 s subs by default; Expert Mode manual targets allow 1 to 30 s. Alt-azimuth only, no EQ mode. Optional clip-on Vaonis filters: dual-band, light-pollution (CLS) and solar.

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 30 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 Vespera Pro? Did the solid figure match?Anonymous, one tap. It is how the model gets calibrated.

Have an image of the Lagoon Nebula from a Vespera Pro? 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 Vespera Pro