How long should I image the Little Dumbbell with the Vespera 3 from a Bortle 6 sky?

About 43 min of total integration for a solid image, or 2 h 53 min for a showpiece. A quick look takes 11 min.

How many subs is that on the Vespera 3?

At the default 10 s sub length, 260 subs for a solid image from Bortle 6 and 116 from Bortle 3.

Does a dual-band filter help on the Little Dumbbell?

Yes. It is an emission-line object; from Bortle 6 the filter cuts the solid-image time from 43 min to 31 min.

How long to image the Little Dumbbell with the Vaonis Vespera 3

From a Bortle 6 suburban sky, the Vaonis Vespera 3 needs about 43 min (260 subs of 10 s) for a solid image of the Little Dumbbell. A quick look takes 11 min; a showpiece 2 h 53 min. Under a Bortle 3 rural sky the solid figure drops to 19 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 3% of the frame’s short side.

Little Dumbbell 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	4 min26 subs	17 min102 subs	1 h 07 min405 subs
Bortle 2Typical dark site	4 min27 subs	18 min106 subs	1 h 11 min424 subs
Bortle 3Rural	5 min29 subs	19 min116 subs	1 h 17 min461 subs
Bortle 4Rural / suburban transition	6 min35 subs	23 min138 subs	1 h 32 min550 subs
Bortle 5Suburban	7 min44 subs	29 min173 subs	1 h 55 min691 subs
Bortle 6Bright suburban	11 min65 subs	43 min260 subs	2 h 53 min1,038 subs
Bortle 7Suburban / urban transition	18 min107 subs	1 h 11 min425 subs	4 h 43 min1,699 subs
Bortle 8City	28 min171 subs	1 h 54 min682 subs	7 h 34 min2,725 subs
Bortle 9Inner city	51 min308 subs	3 h 25 min1,229 subs	14 h4,913 subs

Adjust in the calculator

Power and kit for this session

Allowing for slewing, focusing and rejected subs, that is about 56 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 Little Dumbbell is 2.7′ × 1.8′ across. The Vespera 3 frames 2.60° × 1.46° at 2.44″ per pixel, so it fills 3% 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	19 min116 subs	29 min173 subs	1 h 11 min425 subs
20 s	17 min52 subs	27 min80 subs	1 h 09 min206 subs
30 s	16 min33 subs	26 min52 subs	1 h 08 min136 subs

With and without the dual-band filter

Solid quality, default sub length.
Filter	Bortle 3	Bortle 5	Bortle 7
No filter	19 min116 subs	29 min173 subs	1 h 11 min425 subs
dual-band (Dual Band filter), clip-on	23 min141 subs	26 min159 subs	39 min236 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 Little Dumbbell

A small, bright-per-pixel planetary in Perseus. Dual-band makes the two lobes and the faint wings much easier.

M76, NGC 650 · Planetary nebula in Perseus · magnitude 10.1 · 2.7′ × 1.8′ · best in Sep, Oct, Nov. Reachable from mid-northern latitudes (UK, northern US, central Europe) and from the south.

Planetary nebulae are small but intensely bright per pixel in OIII and H-alpha, so they respond very well to a dual-band filter and do not need much time for the main shell. The faint outer halos most of them have are a different proposition and need hours. Keep subs short if the central region saturates.

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 Little Dumbbell with your Vespera 3? Did the solid figure match?Anonymous, one tap. It is how the model gets calibrated.

Have an image of the Little Dumbbell 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 Little Dumbbell · All targets for the Vespera 3