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

About 1 h 04 min of total integration for a solid image, or 4 h 16 min for a showpiece. A quick look takes 16 min.

How many subs is that on the Vespera 3?

At the default 10 s sub length, 384 subs for a solid image from Bortle 6 and 151 from Bortle 3.

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

Yes. It is an emission-line object; from Bortle 6 the filter cuts the solid-image time from 1 h 04 min to 41 min.

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

From a Bortle 6 suburban sky, the Vaonis Vespera 3 needs about 1 h 04 min (384 subs of 10 s) for a solid image of the Trifid Nebula. A quick look takes 16 min; a showpiece 4 h 16 min. Under a Bortle 3 rural sky the solid figure drops to 25 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 32% of the frame’s short side.

Trifid 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	5 min32 subs	21 min128 subs	1 h 25 min512 subs
Bortle 2Typical dark site	6 min34 subs	23 min136 subs	1 h 30 min543 subs
Bortle 3Rural	6 min38 subs	25 min151 subs	1 h 40 min603 subs
Bortle 4Rural / suburban transition	8 min47 subs	31 min187 subs	2 h 04 min747 subs
Bortle 5Suburban	10 min61 subs	41 min244 subs	2 h 42 min975 subs
Bortle 6Bright suburban	16 min96 subs	1 h 04 min384 subs	4 h 16 min1,534 subs
Bortle 7Suburban / urban transition	27 min163 subs	1 h 48 min651 subs	7 h 13 min2,601 subs
Bortle 8City	44 min266 subs	2 h 57 min1,064 subs	12 h4,256 subs
Bortle 9Inner city	1 h 21 min487 subs	5 h 24 min1,947 subs	22 h7,788 subs

Adjust in the calculator

Power and kit for this session

Allowing for slewing, focusing and rejected subs, that is about 1 h 23 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 Trifid Nebula is 28′ across. The Vespera 3 frames 2.60° × 1.46° at 2.44″ per pixel, so it fills 32% 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	25 min151 subs	41 min244 subs	1 h 48 min651 subs
20 s	22 min65 subs	37 min112 subs	1 h 45 min315 subs
30 s	20 min41 subs	36 min72 subs	1 h 44 min208 subs

With and without the dual-band filter

Solid quality, default sub length.
Filter	Bortle 3	Bortle 5	Bortle 7
No filter	25 min151 subs	41 min244 subs	1 h 48 min651 subs
dual-band (Dual Band filter), clip-on	29 min177 subs	34 min206 subs	55 min330 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 Trifid Nebula

Red emission, blue reflection and dark lanes in one object. Shoot it without a filter to keep the blue, or dual-band for the red.

M20, NGC 6514 · Emission nebula in Sagittarius · magnitude 6.3 · 28′ · 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.

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Imaged the Trifid 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 Trifid 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 Trifid Nebula · All targets for the Vespera 3