How long should I image the Eagle Nebula with the Seestar S50 Pro from a Bortle 6 sky?

About 1 h 08 min of total integration for a solid image, or 4 h 33 min for a showpiece. A quick look takes 17 min.

How many subs is that on the Seestar S50 Pro?

At the default 10 s sub length, 410 subs for a solid image from Bortle 6 and 294 from Bortle 3.

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

Yes. It is an emission-line object; from Bortle 6 the filter cuts the solid-image time from 1 h 44 min to 1 h 08 min.

How long to image the Eagle Nebula with the ZWO Seestar S50 Pro

From a Bortle 6 suburban sky, the ZWO Seestar S50 Pro needs about 1 h 08 min (410 subs of 10 s with the built-in dual-band (LP filter) filter) for a solid image of the Eagle Nebula. A quick look takes 17 min; a showpiece 4 h 33 min. Under a Bortle 3 rural sky the solid figure drops to 49 min. At Bortle 6 the limit is a mix of skyglow and read noise. In this scope's field it fills 42% of the frame’s short side.

Eagle Nebula with the ZWO Seestar S50 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	12 min71 subs	47 min283 subs	3 h 08 min1,130 subs
Bortle 2Typical dark site	12 min72 subs	48 min287 subs	3 h 11 min1,145 subs
Bortle 3Rural	12 min74 subs	49 min294 subs	3 h 16 min1,175 subs
Bortle 4Rural / suburban transition	13 min78 subs	52 min312 subs	3 h 28 min1,247 subs
Bortle 5Suburban	14 min85 subs	57 min340 subs	3 h 47 min1,360 subs
Bortle 6Bright suburban	17 min103 subs	1 h 08 min410 subs	4 h 33 min1,639 subs
Bortle 7Suburban / urban transition	23 min136 subs	1 h 30 min543 subs	6 h 02 min2,171 subs
Bortle 8City	31 min188 subs	2 h 05 min749 subs	8 h 19 min2,996 subs
Bortle 9Inner city	50 min298 subs	3 h 18 min1,189 subs	13 h4,755 subs

Adjust in the calculator

Power and kit for this session

Allowing for slewing, focusing and rejected subs, that is about 1 h 29 min of run time. The Seestar S50 Pro’s battery (rated about 9 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 PD power bank 20000mAh 30WAccepts 12 V 3 A PD, so a 30 W bank tops up the 10,000 mAh cell while imaging.
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Seestar S50 Pro dew shieldDew heater is built in; a shield adds margin on damp nights. Check the listing says S50 Pro.
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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 Eagle Nebula is 35′ × 28′ across. The Seestar S50 Pro frames 2.45° × 1.38° at 2.30″ per pixel, so it fills 42% of the frame’s short side.

Longer subs

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

Sub length	Bortle 3	Bortle 5	Bortle 7
10 s	49 min294 subs	57 min340 subs	1 h 30 min543 subs
20 s	36 min108 subs	44 min131 subs	1 h 17 min233 subs
30 s	32 min64 subs	39 min79 subs	1 h 13 min147 subs
60 s	30 min30 subs	35 min35 subs	1 h 09 min69 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)	41 min245 subs	1 h 06 min397 subs	2 h 56 min1,058 subs
dual-band (LP filter)	49 min294 subs	57 min340 subs	1 h 30 min543 subs

About the Eagle Nebula

Home of the Pillars of Creation. The cluster comes fast; the pillars and surrounding nebulosity need a dual-band filter and patience.

M16, NGC 6611, IC 4703 · Emission nebula in Serpens · magnitude 6.0 · 35′ × 28′ · best in Jun, Jul, Aug. 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 S50 Pro

The S50 optics at 260 mm on an 8 MP 1/1.2-inch sensor: a wider, taller field, four times the pixels, and 60 s subs in EQ mode. Per pixel it is a whisker slower than the S50 because of the longer focal length; the long subs make it the better dark-site scope.

10, 20 and 30 s in Alt-Az; 60 s only in EQ mode, and 60 s is the ceiling. 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 S50 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 Eagle Nebula with your Seestar S50 Pro? Did the solid figure match?Anonymous, one tap. It is how the model gets calibrated.

Have an image of the Eagle Nebula from a Seestar S50 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 Eagle Nebula · All targets for the Seestar S50 Pro