How long should I image the Bode's Galaxy with the Seestar S30 from a Bortle 6 sky?

About 1 h 07 min of total integration for a solid image, or 4 h 28 min for a showpiece. A quick look takes 17 min.

How many subs is that on the Seestar S30?

At the default 10 s sub length, 402 subs for a solid image from Bortle 6 and 171 from Bortle 3.

Does a dual-band filter help on the Bode's Galaxy?

No. The Bode's Galaxy is a broadband target and a dual-band filter blocks most of its light. Shoot without a filter.

How long to image the Bode's Galaxy with the ZWO Seestar S30

From a Bortle 6 suburban sky, the ZWO Seestar S30 needs about 1 h 07 min (402 subs of 10 s) for a solid image of the Bode's Galaxy. A quick look takes 17 min; a showpiece 4 h 28 min. Under a Bortle 3 rural sky the solid figure drops to 28 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 38% of the frame’s short side.

Bode's Galaxy with the ZWO Seestar S30: 10 s subs.
Sky	Quick lookTarget obvious, still noisy	SolidClean enough to share	ShowpieceSmooth faint detail, print-worthy
Bortle 1Excellent dark site	6 min38 subs	25 min149 subs	1 h 39 min594 subs
Bortle 2Typical dark site	7 min40 subs	26 min157 subs	1 h 44 min626 subs
Bortle 3Rural	7 min43 subs	28 min171 subs	1 h 54 min684 subs
Bortle 4Rural / suburban transition	9 min52 subs	34 min207 subs	2 h 18 min827 subs
Bortle 5Suburban	11 min66 subs	44 min263 subs	2 h 55 min1,052 subs
Bortle 6Bright suburban	17 min101 subs	1 h 07 min402 subs	4 h 28 min1,606 subs
Bortle 7Suburban / urban transition	28 min167 subs	1 h 51 min666 subs	7 h 23 min2,661 subs
Bortle 8City	45 min269 subs	2 h 59 min1,075 subs	12 h4,299 subs
Bortle 9Inner city	1 h 21 min487 subs	5 h 25 min1,948 subs	22 h7,792 subs

Adjust in the calculator

Power and kit for this session

Allowing for slewing, focusing and rejected subs, that is about 1 h 27 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 February 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 Bode's Galaxy is 27′ × 14′ across. The Seestar S30 frames 2.13° × 1.20° at 3.99″ per pixel, so it fills 38% 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 min171 subs	44 min263 subs	1 h 51 min666 subs
20 s	23 min70 subs	39 min116 subs	1 h 46 min318 subs
30 s	22 min44 subs	37 min74 subs	1 h 44 min208 subs
60 s	30 min30 subs	35 min36 subs	1 h 42 min103 subs

Leave the dual-band filter out for the Bode's Galaxy. It is a galaxy, and it shines right across the spectrum. A dual-band filter keeps two emission lines and throws the rest away, so most of the light you came for is being stopped along with the sky. From a Bortle 6 sky it would be roughly 13 times slower.

About the Bode's Galaxy

A big, bright grand-design spiral that circles the pole for northern imagers, so it is available all year. Shares a frame with M82.

M81, NGC 3031 · Galaxy in Ursa Major · magnitude 6.9 · 27′ × 14′ · best in Jan, Feb, Mar. Reachable from mid-northern latitudes (UK, northern US, central Europe) and from the south.

Galaxies are broadband targets: their light is mostly starlight spread across the spectrum, so a dual-band filter throws most of it away and makes things slower, not faster. Shoot without a filter (or with a plain UV/IR cut) and rely on total time and a dark sky. The core of a galaxy is usually many times brighter than its outer disc, so a short stack shows the nucleus long before the arms; the figures here are for the arms and disc, not the core.

Field rotation in Alt-Az mode crops the edges of the stack over a long session, so on a big galaxy re-centre now and then or use EQ mode where your scope supports it.

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 Bode's Galaxy with your Seestar S30? Did the solid figure match?Anonymous, one tap. It is how the model gets calibrated.

Have an image of the Bode's Galaxy 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 Bode's Galaxy · All targets for the Seestar S30