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

About 31 min of total integration for a solid image, or 2 h 04 min for a showpiece. A quick look takes 8 min.

How many subs is that on the Vespera 3?

At the default 10 s sub length, 187 subs for a solid image from Bortle 6 and 81 from Bortle 3.

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

Yes. It is an emission-line object; from Bortle 6 the filter cuts the solid-image time from 31 min to 22 min.

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

From a Bortle 6 suburban sky, the Vaonis Vespera 3 needs about 31 min (187 subs of 10 s) for a solid image of the Omega Nebula. A quick look takes 8 min; a showpiece 2 h 04 min. Under a Bortle 3 rural sky the solid figure drops to 13 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 fills 13% of the frame’s short side.

Omega 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	3 min18 subs	12 min71 subs	47 min283 subs
Bortle 2Typical dark site	3 min19 subs	12 min75 subs	49 min297 subs
Bortle 3Rural	3 min21 subs	13 min81 subs	54 min324 subs
Bortle 4Rural / suburban transition	4 min25 subs	16 min98 subs	1 h 05 min389 subs
Bortle 5Suburban	5 min31 subs	20 min123 subs	1 h 22 min492 subs
Bortle 6Bright suburban	8 min47 subs	31 min187 subs	2 h 04 min745 subs
Bortle 7Suburban / urban transition	13 min77 subs	51 min307 subs	3 h 24 min1,226 subs
Bortle 8City	21 min124 subs	1 h 22 min494 subs	5 h 29 min1,974 subs
Bortle 9Inner city	37 min223 subs	2 h 29 min892 subs	9 h 55 min3,568 subs

Adjust in the calculator

Power and kit for this session

Allowing for slewing, focusing and rejected subs, that is about 40 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.
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How it frames

The Omega Nebula is 11′ across. The Vespera 3 frames 2.60° × 1.46° at 2.44″ per pixel, so it fills 13% of the frame’s short side.

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	13 min81 subs	20 min123 subs	51 min307 subs
20 s	12 min36 subs	19 min57 subs	50 min149 subs
30 s	15 min30 subs	18 min37 subs	49 min98 subs

With and without the dual-band filter

Solid quality, default sub length.
Filter	Bortle 3	Bortle 5	Bortle 7
No filter	13 min81 subs	20 min123 subs	51 min307 subs
dual-band (Dual Band filter), clip-on	16 min99 subs	19 min112 subs	28 min168 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 Omega Nebula

A bright, compact swan-shaped emission nebula, one of the brightest in the sky per unit area. Excellent from suburban skies.

M17, NGC 6618, Swan Nebula · Emission nebula in Sagittarius · magnitude 6.0 · 11′ · 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 Omega 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 Omega 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 Omega Nebula · All targets for the Vespera 3