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

About 36 min of total integration for a solid image, or 2 h 25 min for a showpiece. A quick look takes 9 min.

How many subs is that on the Seestar S30?

At the default 10 s sub length, 219 subs for a solid image from Bortle 6 and 167 from Bortle 3.

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

Yes. It is an emission-line object; from Bortle 6 the filter cuts the solid-image time from 50 min to 36 min.

How long to image the Tarantula Nebula with the ZWO Seestar S30

From a Bortle 6 suburban sky, the ZWO Seestar S30 needs about 36 min (219 subs of 10 s with the built-in dual-band (LP filter) filter) for a solid image of the Tarantula Nebula. A quick look takes 9 min; a showpiece 2 h 25 min. Under a Bortle 3 rural sky the solid figure drops to 28 min. At Bortle 6 the limit is a mix of skyglow and read noise. In this scope's field it fills 56% of the frame’s short side.

Tarantula Nebula with the ZWO Seestar S30: 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	7 min41 subs	27 min162 subs	1 h 48 min647 subs
Bortle 2Typical dark site	7 min41 subs	27 min164 subs	1 h 49 min654 subs
Bortle 3Rural	7 min42 subs	28 min167 subs	1 h 51 min667 subs
Bortle 4Rural / suburban transition	7 min44 subs	29 min175 subs	1 h 56 min699 subs
Bortle 5Suburban	8 min47 subs	31 min188 subs	2 h 05 min749 subs
Bortle 6Bright suburban	9 min55 subs	36 min219 subs	2 h 25 min873 subs
Bortle 7Suburban / urban transition	12 min70 subs	46 min277 subs	3 h 05 min1,108 subs
Bortle 8City	15 min93 subs	1 h 01 min369 subs	4 h 05 min1,473 subs
Bortle 9Inner city	23 min141 subs	1 h 34 min563 subs	6 h 15 min2,251 subs

Adjust in the calculator

Power and kit for this session

Allowing for slewing, focusing and rejected subs, that is about 47 min of run time. The Seestar S30’s battery (rated about 6 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, and 30% off the battery for a December night.)

USB-C power bank 10000mAh 5V 3A6,000 mAh inside; a 10,000 mAh 5 V 3 A bank roughly doubles a session.
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Seestar S30 dew shieldHeater is built in; a cheap shield reduces dew and stray light.
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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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hand warmers long lastingAir-activated packs give hours of heat for the person; winter nights are long and you spend most of them standing still.
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How it frames

The Tarantula Nebula is 40′ × 25′ across. The Seestar S30 frames 2.13° × 1.20° at 3.99″ per pixel, so it fills 56% 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	28 min167 subs	31 min188 subs	46 min277 subs
20 s	20 min61 subs	24 min71 subs	38 min116 subs
30 s	18 min36 subs	21 min42 subs	36 min72 subs
60 s	30 min30 subs	30 min30 subs	33 min34 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)	22 min130 subs	33 min197 subs	1 h 22 min490 subs
dual-band (LP filter)	28 min167 subs	31 min188 subs	46 min277 subs

About the Tarantula Nebula

The giant star-forming region in the Large Magellanic Cloud, bright enough to see naked-eye from another galaxy. Far south only.

NGC 2070, Caldwell 103, 30 Doradus · Emission nebula in Dorado · magnitude 8.0 · 40′ × 25′ · best in Nov, Dec, Jan. Southern hemisphere only.

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

Wider and lighter than the S50 with the same 2.9 µm pixels, so its per-pixel speed on extended targets is close despite the smaller aperture. Ideal for big nebulae.

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.

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 S30ZWO 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 Tarantula Nebula with your Seestar S30? Did the solid figure match?Anonymous, one tap. It is how the model gets calibrated.

Have an image of the Tarantula Nebula from a Seestar S30? Email it with your total time and sky to [email protected] and it goes here, credited.

Same target, other telescopes

All telescopes for the Tarantula Nebula · All targets for the Seestar S30