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

About 32 min of total integration for a solid image, or 2 h 10 min for a showpiece. A quick look takes 8 min.

How many subs is that on the Vespera II?

At the default 10 s sub length, 195 subs for a solid image from Bortle 6 and 86 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 32 min to 23 min.

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

From a Bortle 6 suburban sky, the Vaonis Vespera II needs about 32 min (195 subs of 10 s) for a solid image of the Omega Nebula. A quick look takes 8 min; a showpiece 2 h 10 min. Under a Bortle 3 rural sky the solid figure drops to 14 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 II: 10 s subs.
Sky	Quick lookTarget obvious, still noisy	SolidClean enough to share	ShowpieceSmooth faint detail, print-worthy
Bortle 1Excellent dark site	3 min19 subs	12 min75 subs	50 min299 subs
Bortle 2Typical dark site	3 min20 subs	13 min79 subs	52 min313 subs
Bortle 3Rural	4 min22 subs	14 min86 subs	57 min341 subs
Bortle 4Rural / suburban transition	4 min26 subs	17 min103 subs	1 h 08 min409 subs
Bortle 5Suburban	5 min33 subs	21 min129 subs	1 h 26 min516 subs
Bortle 6Bright suburban	8 min49 subs	32 min195 subs	2 h 10 min779 subs
Bortle 7Suburban / urban transition	13 min81 subs	53 min321 subs	3 h 33 min1,281 subs
Bortle 8City	21 min129 subs	1 h 26 min515 subs	5 h 43 min2,059 subs
Bortle 9Inner city	39 min233 subs	2 h 35 min930 subs	10 h3,719 subs

Adjust in the calculator

Power and kit for this session

Allowing for slewing, focusing and rejected subs, that is about 42 min of run time. The Vespera II’s battery (rated about 4 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 30WOnly four hours inside; Vaonis specifies a 30 W PD source. C-to-C cable not included.
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Vaonis Vespera hygrometer sensorTriggers the built-in demister automatically; the correct dew accessory for the II.
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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 Omega Nebula is 11′ across. The Vespera II frames 2.55° × 1.44° at 2.39″ 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, no EQ mode. Time for a solid image by sub length:

Sub length	Bortle 3	Bortle 5	Bortle 7
10 s	14 min86 subs	21 min129 subs	53 min321 subs
20 s	12 min38 subs	20 min60 subs	52 min155 subs
30 s	15 min30 subs	19 min39 subs	51 min103 subs

With and without the dual-band filter

Solid quality, default sub length.
Filter	Bortle 3	Bortle 5	Bortle 7
No filter	14 min86 subs	21 min129 subs	53 min321 subs
dual-band (Dual Band filter), clip-on	17 min105 subs	20 min118 subs	29 min177 subs

The Vespera II has no built-in dual-band filter. Optional clip-on Vaonis filters: dual-band, light-pollution (CLS) and solar; the app detects which is fitted. 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 II

A 50 mm quadruplet on an 8 MP sensor with Vaonis’s mosaic mode for wide fields. Same optics class as the Seestar S50, four times the pixels.

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; the app detects which is fitted.

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 IIVaonis 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 II? 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 II? 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 II