How long should I image the Dumbbell Nebula with the Vespera II 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 II?

At the default 10 s sub length, 163 subs for a solid image from Bortle 6 and 76 from Bortle 3.

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

Yes. It is an emission-line object; from Bortle 6 the filter cuts the solid-image time from 27 min to 20 min.

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

From a Bortle 6 suburban sky, the Vaonis Vespera II needs about 27 min (163 subs of 10 s) for a solid image of the Dumbbell Nebula. A quick look takes 7 min; a showpiece 1 h 48 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 9% of the frame’s short side.

Dumbbell 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 min17 subs	11 min67 subs	45 min268 subs
Bortle 2Typical dark site	3 min18 subs	12 min70 subs	47 min280 subs
Bortle 3Rural	3 min19 subs	13 min76 subs	50 min302 subs
Bortle 4Rural / suburban transition	4 min23 subs	15 min89 subs	59 min356 subs
Bortle 5Suburban	5 min28 subs	18 min111 subs	1 h 13 min441 subs
Bortle 6Bright suburban	7 min41 subs	27 min163 subs	1 h 48 min649 subs
Bortle 7Suburban / urban transition	11 min66 subs	44 min262 subs	2 h 54 min1,045 subs
Bortle 8City	17 min104 subs	1 h 09 min416 subs	4 h 37 min1,661 subs
Bortle 9Inner city	31 min186 subs	2 h 04 min744 subs	8 h 16 min2,975 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 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 Dumbbell Nebula is 8′ × 5.7′ across. The Vespera II frames 2.55° × 1.44° at 2.39″ per pixel, so it fills 9% 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	13 min76 subs	18 min111 subs	44 min262 subs
20 s	11 min34 subs	17 min51 subs	42 min127 subs
30 s	15 min30 subs	17 min34 subs	42 min84 subs

With and without the dual-band filter

Solid quality, default sub length.
Filter	Bortle 3	Bortle 5	Bortle 7
No filter	13 min76 subs	18 min111 subs	44 min262 subs
dual-band (Dual Band filter), clip-on	16 min94 subs	17 min105 subs	25 min151 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 Dumbbell Nebula

The biggest, brightest planetary nebula for northern observers. Bright enough to look good in twenty minutes, and dual-band brings out the outer shell.

M27, NGC 6853 · Planetary nebula in Vulpecula · magnitude 7.4 · 8′ × 5.7′ · best in Jun, Jul, Aug. 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 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 Dumbbell 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 Dumbbell 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 Dumbbell Nebula · All targets for the Vespera II