How long should I image the Pacman Nebula with the Seestar S30 Pro from a Bortle 6 sky?

About 2 h 02 min of total integration for a solid image, or 8 h 09 min for a showpiece. A quick look takes 31 min.

How many subs is that on the Seestar S30 Pro?

At the default 10 s sub length, 734 subs for a solid image from Bortle 6 and 522 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 3 h 08 min to 2 h 02 min.

How long to image the Pacman Nebula with the ZWO Seestar S30 Pro

From a Bortle 6 suburban sky, the ZWO Seestar S30 Pro needs about 2 h 02 min (734 subs of 10 s with the built-in dual-band (LP filter) filter) for a solid image of the Pacman Nebula. A quick look takes 31 min; a showpiece 8 h 09 min. Under a Bortle 3 rural sky the solid figure drops to 1 h 27 min. At Bortle 6 the limit is a mix of skyglow and read noise. In this scope's field it fills 26% of the frame’s short side.

Pacman Nebula with the ZWO Seestar S30 Pro: 10 s subs with the built-in dual-band (LP filter) filter.
Sky	Quick lookTarget obvious, still noisy	SolidClean enough to share	ShowpieceSmooth faint detail, print-worthy
Bortle 1Excellent dark site	21 min126 subs	1 h 23 min501 subs	5 h 34 min2,004 subs
Bortle 2Typical dark site	21 min127 subs	1 h 25 min508 subs	5 h 39 min2,032 subs
Bortle 3Rural	22 min131 subs	1 h 27 min522 subs	5 h 48 min2,086 subs
Bortle 4Rural / suburban transition	23 min139 subs	1 h 32 min555 subs	6 h 09 min2,217 subs
Bortle 5Suburban	25 min152 subs	1 h 41 min607 subs	6 h 44 min2,425 subs
Bortle 6Bright suburban	31 min184 subs	2 h 02 min734 subs	8 h 09 min2,935 subs
Bortle 7Suburban / urban transition	41 min245 subs	2 h 43 min977 subs	11 h3,906 subs
Bortle 8City	56 min339 subs	3 h 46 min1,354 subs	15 h5,415 subs
Bortle 9Inner city	1 h 30 min540 subs	6 h2,158 subs	24 h8,632 subs

Adjust in the calculator

Power and kit for this session

Allowing for slewing, focusing and rejected subs, that is about 2 h 39 min of run time. The Seestar S30 Pro’s battery (rated about 5 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 power bank 10000mAh 5V 3A5 V 3 A input and it runs while charging.
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Seestar S30 Pro dew shieldActive anti-dew is built in; a shield adds margin. The S30 Pro front differs from the S30, so check the listing.
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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 Seestar S30 Pro frames 3.99° × 2.24° at 3.74″ per pixel, so it fills 26% of the frame’s short side.

Longer subs

10, 20 and 30 s in Alt-Az; 60 s only in EQ mode, which needs the TH10 head. Time for a solid image by sub length:

Sub length	Bortle 3	Bortle 5	Bortle 7
10 s	1 h 27 min522 subs	1 h 41 min607 subs	2 h 43 min977 subs
20 s	1 h 02 min186 subs	1 h 16 min228 subs	2 h 18 min413 subs
30 s	53 min107 subs	1 h 08 min136 subs	2 h 09 min259 subs
60 s	45 min46 subs	59 min60 subs	2 h 01 min121 subs

With and without the dual-band filter

Solid quality, default sub length.
Filter	Bortle 3	Bortle 5	Bortle 7
UV/IR-cut (no light-pollution filter)	1 h 12 min433 subs	1 h 58 min710 subs	5 h 20 min1,920 subs
dual-band (LP filter)	1 h 27 min522 subs	1 h 41 min607 subs	2 h 43 min977 subs

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 ZWO Seestar S30 Pro

The S30 optics upgraded to a quadruplet in front of an 8 MP IMX585. Same speed per pixel as the S30, four times the pixels, so you can crop hard.

10, 20 and 30 s in Alt-Az; 60 s only in EQ mode, which needs the TH10 head. Built-in UV/IR-cut, dual-band (OIII 30 nm / Hα 20 nm) and dark filters on the telephoto camera.

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 60 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 Seestar S30 ProZWO store Direct Amazon UK Amazon USThe ZWO 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 Seestar S30 Pro? Did the solid figure match?Anonymous, one tap. It is how the model gets calibrated.

Have an image of the Pacman Nebula from a Seestar S30 Pro? 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 Seestar S30 Pro