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

About 10 min of total integration for a solid image, or 41 min for a showpiece. A quick look takes 3 min.

How many subs is that on the Seestar S30?

At the default 10 s sub length, 62 subs for a solid image from Bortle 6 and 51 from Bortle 3.

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

Yes. It is an emission-line object; from Bortle 6 the filter cuts the solid-image time from 13 min to 10 min.

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

From a Bortle 6 suburban sky, the ZWO Seestar S30 needs about 10 min (62 subs of 10 s with the built-in dual-band (LP filter) filter) for a solid image of the Carina Nebula. A quick look takes 3 min; a showpiece 41 min. Under a Bortle 3 rural sky the solid figure drops to 8 min. At Bortle 6 the limit is a mix of skyglow and read noise. In this scope's field it is 1.7× wider than the frame.

Carina 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	2 min13 subs	8 min50 subs	33 min197 subs
Bortle 2Typical dark site	2 min13 subs	8 min50 subs	33 min198 subs
Bortle 3Rural	2 min13 subs	8 min51 subs	33 min201 subs
Bortle 4Rural / suburban transition	2 min13 subs	9 min52 subs	35 min208 subs
Bortle 5Suburban	2 min14 subs	9 min55 subs	37 min220 subs
Bortle 6Bright suburban	3 min16 subs	10 min62 subs	41 min248 subs
Bortle 7Suburban / urban transition	3 min19 subs	13 min76 subs	50 min302 subs
Bortle 8City	4 min25 subs	16 min97 subs	1 h 04 min386 subs
Bortle 9Inner city	6 min36 subs	23 min141 subs	1 h 34 min564 subs

Adjust in the calculator

Power and kit for this session

Allowing for slewing, focusing and rejected subs, that is about 13 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.)

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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How it frames

The Carina Nebula is 120′ across. The Seestar S30 frames 2.13° × 1.20° at 3.99″ per pixel, so it is 1.7× wider than the frame. A mosaic, or choosing the part you want and letting the rest go, is how it gets shot on this scope.

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	8 min51 subs	9 min55 subs	13 min76 subs
20 s	10 min30 subs	10 min30 subs	11 min33 subs
30 s	15 min30 subs	15 min30 subs	15 min30 subs
60 s	30 min30 subs	30 min30 subs	30 min30 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)	6 min39 subs	9 min54 subs	20 min121 subs
dual-band (LP filter)	8 min51 subs	9 min55 subs	13 min76 subs

About the Carina Nebula

Four times the size and brightness of the Orion Nebula, the best emission nebula in the sky. Southern hemisphere only, and easy from anywhere it rises.

NGC 3372, Caldwell 92, Eta Carinae Nebula · Emission nebula in Carina · magnitude 1.0 · 120′ · best in Feb, Mar, Apr. Low or below the horizon from northern Europe; best from the southern US southwards.

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 Carina 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 Carina 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 Carina Nebula · All targets for the Seestar S30