Is the Seestar S50 faster than the eQuinox 2?

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?

The eQuinox 2, with its finer pixel scale of 1.33″ per pixel.

Seestar S50 vs eQuinox 2: which is faster for deep-sky imaging?

ZWO Seestar S50 against Unistellar eQuinox 2, 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 shows 1.28° × 0.72° against 0.76° × 0.57°, so big targets such as the Andromeda Galaxy, the North America Nebula and the Pleiades fit with room to spare where the eQuinox 2 needs a mosaic or a tight crop.

Detail. The eQuinox 2 samples at 1.33″ per pixel against 2.39″, so it pulls finer structure from small targets: planetary nebulae, globular cores, galaxy arms.

Subs and dark skies. The Seestar S50 goes up to 60 s subs in EQ mode, the eQuinox 2 tops out at 4 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 has a dual-band filter built in; the eQuinox 2 does not, which costs it heavily on emission nebulae from any suburban sky.

Specifications side by side

Spec	Seestar S50	eQuinox 2
Aperture	50 mm	114 mm
Focal length	250 mm (f/5.0)	450 mm (f/3.9)
Sensor	Sony IMX462, 2.1 MP	IMX347-class, 2.9 µm (Unistellar does not name it), 3.2 MP
Pixel size	2.9 µm	2.9 µm
Pixel scale	2.39″/px	1.33″/px
Field of view	1.28° × 0.72°	0.76° × 0.57°
Sub exposures	10 s, 20 s, 30 s, 60 s	4 s
Dual-band filter	Built in (LP filter)	None
“No filter” position	UV/IR-cut	No filter
Read noise used	1 e⁻	1.8 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	eQuinox 2	Faster
Andromeda GalaxyGalaxy	1 h 27 min525 subs	1 h 19 min1,191 subs	eQuinox 2 1.1×
Orion NebulaEmission nebula	12 min75 subs	15 min224 subs	Seestar S50 1.2×
North America NebulaEmission nebula	1 h 25 min512 subs	2 h 04 min1,854 subs	Seestar S50 1.4×
Pinwheel GalaxyGalaxy	4 h 37 min1,661 subs	4 h 14 min3,814 subs	eQuinox 2 1.1×
Ring NebulaPlanetary nebula	7 min42 subs	6 min96 subs	eQuinox 2 1.1×
Western Veil NebulaSupernova remnant	1 h 33 min557 subs	2 h 15 min2,028 subs	Seestar S50 1.5×
Hercules ClusterGlobular cluster	7 min44 subs	6 min94 subs	eQuinox 2 1.2×
PleiadesReflection nebula	2 h 42 min971 subs	2 h 28 min2,219 subs	eQuinox 2 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	eQuinox 2	Faster
Andromeda GalaxyGalaxy	34 min204 subs	46 min690 subs	Seestar S50 1.4×
Orion NebulaEmission nebula	10 min58 subs	9 min137 subs	eQuinox 2 1.1×
North America NebulaEmission nebula	59 min357 subs	1 h 11 min1,064 subs	Seestar S50 1.2×
Pinwheel GalaxyGalaxy	1 h 40 min602 subs	2 h 24 min2,164 subs	Seestar S50 1.4×
Ring NebulaPlanetary nebula	6 min36 subs	4 min66 subs	eQuinox 2 1.4×
Western Veil NebulaSupernova remnant	1 h 04 min387 subs	1 h 17 min1,162 subs	Seestar S50 1.2×
Hercules ClusterGlobular cluster	5 min30 subs	4 min60 subs	eQuinox 2 1.3×
PleiadesReflection nebula	1 h362 subs	1 h 25 min1,270 subs	Seestar S50 1.4×

Try the Seestar S50 in the calculator Try the eQuinox 2

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 Unistellar eQuinox 2

A 114 mm Newtonian with five times the light grasp of a 50 mm refractor. Fixed 4 s subs put it in read-noise territory under dark skies, but the aperture carries it. The published field is 45.6′ × 34.2′, a crop of the sensor.

Where to buy the eQuinox 2Amazon UK Unistellar UK Amazon US Unistellar USAffiliate links: As an Amazon Associate I earn from qualifying purchases, at no cost to you.

Other comparisons

All comparisons · Buying guide · Seestar S50 page · eQuinox 2 page