Is the Seestar S50 Pro faster than the Origin Mark II?

From a Bortle 6 sky the Origin Mark II is 2.2× faster on the 30 most popular deep-sky targets; from Bortle 3 the Origin Mark II is 4× faster.

Which is better for small targets like planetary nebulae?

The Origin Mark II, with its finer pixel scale of 1.23″ per pixel.

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

ZWO Seestar S50 Pro against Celestron Origin Mark II, 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 Origin Mark II is 2.2× faster (geometric mean of the solid-image times, each scope on its recommended filter and default subs). From a rural Bortle 3 sky the Origin Mark II is 4× faster.

Field of view. The Seestar S50 Pro shows 2.45° × 1.38° against 1.32° × 0.75°, so big targets such as the Andromeda Galaxy, the North America Nebula and the Pleiades fit with room to spare where the Origin Mark II needs a mosaic or a tight crop.

Detail. The Origin Mark II samples at 1.23″ per pixel against 2.30″, so it pulls finer structure from small targets: planetary nebulae, globular cores, galaxy arms.

Subs and dark skies. The Seestar S50 Pro goes up to 60 s subs in EQ mode, the Origin Mark II tops out at 30 s. That matters little from a city, where skyglow sets the floor, and a lot from a dark site, where read noise does.

Filters. The Seestar S50 Pro has a dual-band filter built in; the Origin Mark II does not, which costs it heavily on emission nebulae from any suburban sky.

Specifications side by side

Spec	Seestar S50 Pro	Origin Mark II
Aperture	50 mm	152 mm
Focal length	260 mm (f/5.2)	335 mm (f/2.2)
Sensor	OmniVision OS08B10 (1/1.2″), 8.3 MP	Sony IMX678, 8.4 MP
Pixel size	2.9 µm	2 µm
Pixel scale	2.30″/px	1.23″/px
Field of view	2.45° × 1.38°	1.32° × 0.75°
Sub exposures	10 s, 20 s, 30 s, 60 s	10 s, 15 s, 30 s
Dual-band filter	Built in (LP filter)	Drawer option (Nebula Filter)
“No filter” position	UV/IR-cut	No filter
Read noise used	1 e⁻	0.6 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 Pro	Origin Mark II	Faster
Andromeda GalaxyGalaxy	1 h 36 min575 subs	32 min191 subs	Origin Mark II 3×
Orion NebulaEmission nebula	14 min83 subs	6 min38 subs	Origin Mark II 2.2×
North America NebulaEmission nebula	1 h 36 min574 subs	49 min295 subs	Origin Mark II 1.9×
Pinwheel GalaxyGalaxy	5 h 03 min1,817 subs	1 h 40 min600 subs	Origin Mark II 3×
Ring NebulaPlanetary nebula	8 min46 subs	5 min30 subs	Origin Mark II 1.5×
Western Veil NebulaSupernova remnant	1 h 44 min625 subs	54 min322 subs	Origin Mark II 1.9×
Hercules ClusterGlobular cluster	8 min48 subs	5 min30 subs	Origin Mark II 1.6×
PleiadesReflection nebula	2 h 57 min1,063 subs	59 min352 subs	Origin Mark II 3×

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 Pro	Origin Mark II	Faster
Andromeda GalaxyGalaxy	38 min227 subs	10 min60 subs	Origin Mark II 4×
Orion NebulaEmission nebula	11 min65 subs	5 min30 subs	Origin Mark II 2.2×
North America NebulaEmission nebula	1 h 08 min407 subs	15 min88 subs	Origin Mark II 5×
Pinwheel GalaxyGalaxy	1 h 52 min672 subs	28 min168 subs	Origin Mark II 4×
Ring NebulaPlanetary nebula	7 min40 subs	5 min30 subs	Origin Mark II 1.3×
Western Veil NebulaSupernova remnant	1 h 13 min441 subs	16 min95 subs	Origin Mark II 5×
Hercules ClusterGlobular cluster	5 min30 subs	5 min30 subs	Same
PleiadesReflection nebula	1 h 07 min404 subs	17 min103 subs	Origin Mark II 4×

Try the Seestar S50 Pro in the calculator Try the Origin Mark II

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.

About the Celestron Origin Mark II

The Origin Mark II (late 2025): the same 6-inch f/2.2 RASA with an 8 MP IMX678 in place of the original 6 MP IMX178. Smaller pixels for finer detail, a quieter sensor, and still the fastest system here by a wide margin.

Where to buy the Origin Mark IICelestron store Direct Amazon UK Amazon USThe Celestron 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

Seestar S50 Pro

Origin Mark II

All comparisons · Buying guide · Seestar S50 Pro page · Origin Mark II page