Is the Seestar S50 faster than the Seestar S50 Pro?

From a Bortle 6 sky the Seestar S50 is 1.1× faster on the 30 most popular deep-sky targets; from Bortle 3 the Seestar S50 is 1.1× faster.

Which is better for small targets like planetary nebulae?

Neither has a meaningful advantage; their pixel scales are similar.

Seestar S50 vs Seestar S50 Pro: which is faster for deep-sky imaging?

ZWO Seestar S50 against ZWO Seestar S50 Pro, on the same targets from the same skies, using the same photon-budget model as the rest of the site. Times are for a solid image; the calculator gives quick-look and showpiece figures too.

Speed. Across the 30 most popular targets from a suburban Bortle 6 sky, the Seestar S50 is 1.1× faster (geometric mean of the solid-image times, each scope on its recommended filter and default subs). From a rural Bortle 3 sky the Seestar S50 is 1.1× faster.

Field of view. The Seestar S50 Pro shows 2.45° × 1.38° against 1.28° × 0.72°, so big targets such as the Andromeda Galaxy, the North America Nebula and the Pleiades fit with room to spare where the Seestar S50 needs a mosaic or a tight crop.

Detail. Pixel scales are within 10% of each other, so neither has a real detail advantage.

Subs and dark skies. Both top out at 60 s subs, so neither has an edge at read-noise-limited dark sites.

Filters. Both carry a dual-band filter, which is what makes emission nebulae practical from a lit sky.

Specifications side by side

Spec	Seestar S50	Seestar S50 Pro
Aperture	50 mm	50 mm
Focal length	250 mm (f/5.0)	260 mm (f/5.2)
Sensor	Sony IMX462, 2.1 MP	OmniVision OS08B10 (1/1.2″), 8.3 MP
Pixel size	2.9 µm	2.9 µm
Pixel scale	2.39″/px	2.30″/px
Field of view	1.28° × 0.72°	2.45° × 1.38°
Sub exposures	10 s, 20 s, 30 s, 60 s	10 s, 20 s, 30 s, 60 s
Dual-band filter	Built in (LP filter)	Built in (LP filter)
“No filter” position	UV/IR-cut	UV/IR-cut
Read noise used	1 e⁻	1 e⁻

Timed on the same targets

Suburban sky (Bortle 6)

Total integration for a solid image from a Bortle 6 sky, default subs, recommended filter for each scope.
Target	Seestar S50	Seestar S50 Pro	Faster
Andromeda GalaxyGalaxy	1 h 27 min525 subs	1 h 36 min575 subs	Seestar S50 1.1×
Orion NebulaEmission nebula	12 min75 subs	14 min83 subs	Seestar S50 1.1×
North America NebulaEmission nebula	1 h 25 min512 subs	1 h 36 min574 subs	Seestar S50 1.1×
Pinwheel GalaxyGalaxy	4 h 37 min1,661 subs	5 h 03 min1,817 subs	Seestar S50 1.1×
Ring NebulaPlanetary nebula	7 min42 subs	8 min46 subs	Seestar S50 1.1×
Western Veil NebulaSupernova remnant	1 h 33 min557 subs	1 h 44 min625 subs	Seestar S50 1.1×
Hercules ClusterGlobular cluster	7 min44 subs	8 min48 subs	Seestar S50 1.1×
PleiadesReflection nebula	2 h 42 min971 subs	2 h 57 min1,063 subs	Seestar S50 1.1×

Rural sky (Bortle 3)

Total integration for a solid image from a Bortle 3 sky, default subs, recommended filter for each scope.
Target	Seestar S50	Seestar S50 Pro	Faster
Andromeda GalaxyGalaxy	34 min204 subs	38 min227 subs	Seestar S50 1.1×
Orion NebulaEmission nebula	10 min58 subs	11 min65 subs	Seestar S50 1.1×
North America NebulaEmission nebula	59 min357 subs	1 h 08 min407 subs	Seestar S50 1.1×
Pinwheel GalaxyGalaxy	1 h 40 min602 subs	1 h 52 min672 subs	Seestar S50 1.1×
Ring NebulaPlanetary nebula	6 min36 subs	7 min40 subs	Seestar S50 1.1×
Western Veil NebulaSupernova remnant	1 h 04 min387 subs	1 h 13 min441 subs	Seestar S50 1.1×
Hercules ClusterGlobular cluster	5 min30 subs	5 min30 subs	Same
PleiadesReflection nebula	1 h362 subs	1 h 07 min404 subs	Seestar S50 1.1×

Try the Seestar S50 in the calculator Try the Seestar S50 Pro

About the ZWO Seestar S50

The scope that made smart astrophotography mainstream. 50 mm triplet, 2 MP sensor, dual-band filter on a wheel. Alt-Az stacking at 10 s, EQ mode unlocks 60 s. Out of production since 2026 and replaced by the S50 Pro, but there are a great many in use.

Where to buy the Seestar S50ZWO 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.

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.

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.

Other comparisons

All comparisons · Buying guide · Seestar S50 page · Seestar S50 Pro page