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

About 2 h 42 min of total integration for a solid image, or 11 h for a showpiece. A quick look takes 40 min.

How many subs is that on the Vespera II?

At the default 10 s sub length, 971 subs for a solid image from Bortle 6 and 362 from Bortle 3.

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

Yes. It is an emission-line object; from Bortle 6 the filter cuts the solid-image time from 2 h 42 min to 1 h 41 min.

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

From a Bortle 6 suburban sky, the Vaonis Vespera II needs about 2 h 42 min (971 subs of 10 s) for a solid image of the Pacman Nebula. A quick look takes 40 min; a showpiece 11 h. Under a Bortle 3 rural sky the solid figure drops to 1 h. 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 41% of the frame’s short side.

Pacman 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	13 min76 subs	50 min303 subs	3 h 22 min1,210 subs
Bortle 2Typical dark site	13 min81 subs	54 min323 subs	3 h 35 min1,292 subs
Bortle 3Rural	15 min91 subs	1 h362 subs	4 h 01 min1,447 subs
Bortle 4Rural / suburban transition	19 min114 subs	1 h 16 min456 subs	5 h 04 min1,824 subs
Bortle 5Suburban	25 min152 subs	1 h 41 min605 subs	6 h 43 min2,420 subs
Bortle 6Bright suburban	40 min243 subs	2 h 42 min971 subs	11 h3,884 subs
Bortle 7Suburban / urban transition	1 h 10 min418 subs	4 h 38 min1,669 subs	19 h6,673 subs
Bortle 8City	1 h 55 min688 subs	7 h 38 min2,751 subs	31 h11,004 subs
Bortle 9Inner city	3 h 31 min1,265 subs	14 h5,060 subs	56 h20,239 subs

Adjust in the calculator

Power and kit for this session

Allowing for slewing, focusing and rejected subs, that is about 3 h 30 min of run time. The Vespera II’s battery is rated at about 4 h, which is cutting it fine; take a power bank. (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 Pacman Nebula is 35′ × 30′ across. The Vespera II frames 2.55° × 1.44° at 2.39″ per pixel, so it fills 41% 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	1 h362 subs	1 h 41 min605 subs	4 h 38 min1,669 subs
20 s	51 min153 subs	1 h 31 min274 subs	4 h 29 min806 subs
30 s	48 min96 subs	1 h 28 min177 subs	4 h 25 min531 subs

With and without the dual-band filter

Solid quality, default sub length.
Filter	Bortle 3	Bortle 5	Bortle 7
No filter	1 h362 subs	1 h 41 min605 subs	4 h 38 min1,669 subs
dual-band (Dual Band filter), clip-on	1 h 10 min420 subs	1 h 22 min495 subs	2 h 17 min820 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 Pacman Nebula

A bright emission nebula with a dark lane biting into it. Compact, bright, and excellent with a dual-band filter from suburban skies.

NGC 281 · Emission nebula in Cassiopeia · magnitude 7.4 · 35′ × 30′ · best in Sep, Oct, Nov. 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 Pacman 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 Pacman 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 Pacman Nebula · All targets for the Vespera II