How long should I image the Lagoon Nebula with the Vespera 3 from a Bortle 6 sky?

About 27 min of total integration for a solid image, or 1 h 48 min for a showpiece. A quick look takes 7 min.

How many subs is that on the Vespera 3?

At the default 10 s sub length, 162 subs for a solid image from Bortle 6 and 69 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 27 min to 19 min.

How long to image the Lagoon Nebula with the Vaonis Vespera 3

From a Bortle 6 suburban sky, the Vaonis Vespera 3 needs about 27 min (162 subs of 10 s) for a solid image of the Lagoon Nebula. A quick look takes 7 min; a showpiece 1 h 48 min. Under a Bortle 3 rural sky the solid figure drops to 11 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 is just over the frame at 1.0×.

Lagoon Nebula with the Vaonis Vespera 3: 10 s subs.
Sky	Quick lookTarget obvious, still noisy	SolidClean enough to share	ShowpieceSmooth faint detail, print-worthy
Bortle 1Excellent dark site	2 min15 subs	10 min60 subs	40 min240 subs
Bortle 2Typical dark site	3 min16 subs	11 min64 subs	42 min253 subs
Bortle 3Rural	3 min18 subs	11 min69 subs	46 min276 subs
Bortle 4Rural / suburban transition	3 min21 subs	14 min84 subs	56 min334 subs
Bortle 5Suburban	4 min27 subs	18 min106 subs	1 h 11 min424 subs
Bortle 6Bright suburban	7 min41 subs	27 min162 subs	1 h 48 min647 subs
Bortle 7Suburban / urban transition	11 min67 subs	45 min268 subs	2 h 59 min1,072 subs
Bortle 8City	18 min109 subs	1 h 12 min433 subs	4 h 48 min1,731 subs
Bortle 9Inner city	33 min197 subs	2 h 11 min785 subs	8 h 43 min3,137 subs

Adjust in the calculator

Power and kit for this session

Allowing for slewing, focusing and rejected subs, that is about 35 min of run time. The Vespera 3’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 30WVaonis says an external bank extends sessions; 30 W PD as for the II and Pro.
Amazon UK Amazon US
red LED head torchRed light keeps your night vision; white light costs you twenty minutes of dark adaptation every time.
Amazon UK Amazon US

Affiliate links: the retailer pays us a small commission and you pay the same price. These are search links to the named product, not endorsements of a particular listing; check the listing matches your model.

Everything that fits the Vespera 3 →

How it frames

The Lagoon Nebula is 90′ × 40′ across. The Vespera 3 frames 2.60° × 1.46° at 2.44″ per pixel, so it is just over the frame at 1.0×. Point at the part you want; the edges will fall outside the frame.

Longer subs

10 s subs by default; Expert Mode manual targets allow 1 to 30 s. Alt-azimuth only; CovalENS mosaic widens the field to 4.3° × 2.4°. Time for a solid image by sub length:

Sub length	Bortle 3	Bortle 5	Bortle 7
10 s	11 min69 subs	18 min106 subs	45 min268 subs
20 s	10 min31 subs	16 min49 subs	43 min130 subs
30 s	15 min30 subs	16 min32 subs	43 min86 subs

With and without the dual-band filter

Solid quality, default sub length.
Filter	Bortle 3	Bortle 5	Bortle 7
No filter	11 min69 subs	18 min106 subs	45 min268 subs
dual-band (Dual Band filter), clip-on	14 min84 subs	16 min95 subs	24 min145 subs

The Vespera 3 has no built-in dual-band filter. Optional clip-on Vaonis filters: dual-band, light-pollution (CLS) and solar. The new optical baffle is not a substitute for a CLS filter. 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 3

The 2026 Vespera: same 50 mm quadruplet class as the II on an 8 MP IMX585, with a 24 MP mosaic mode and 11 hours of battery. Per pixel it behaves like a Seestar S50 Pro without the built-in dual-band filter.

10 s subs by default; Expert Mode manual targets allow 1 to 30 s. Alt-azimuth only; CovalENS mosaic widens the field to 4.3° × 2.4°. Optional clip-on Vaonis filters: dual-band, light-pollution (CLS) and solar. The new optical baffle is not a substitute for a CLS filter.

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.

Where to buy the Vespera 3Vaonis store Direct Amazon UK Amazon USThe Vaonis store link is a plain link; the others are affiliate links. As an Amazon Associate I earn from qualifying purchases, at no cost to you.

Imaged the Lagoon Nebula with your Vespera 3? 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 3? 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 3