Is the Seestar S50 faster than the Vespera 3?

From a Bortle 6 sky the Seestar S50 is 1.2× faster on the 30 most popular deep-sky targets; from Bortle 3 the Vespera 3 is 1.2× faster.

Which is better for small targets like planetary nebulae?

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

Seestar S50 vs Vespera 3: which is faster for deep-sky imaging?

ZWO Seestar S50 against Vaonis Vespera 3, 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 1.2× faster (geometric mean of the solid-image times, each scope on its recommended filter and default subs). From a rural Bortle 3 sky the Vespera 3 is 1.2× faster, so the ranking flips under dark skies.

Field of view. The Vespera 3 shows 2.60° × 1.46° 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. The Seestar S50 goes up to 60 s subs in EQ mode, the Vespera 3 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 has a dual-band filter built in; the Vespera 3 does not, which costs it heavily on emission nebulae from any suburban sky.

Specifications side by side

Spec	Seestar S50	Vespera 3
Aperture	50 mm	50 mm
Focal length	250 mm (f/5.0)	245 mm (f/4.9)
Sensor	Sony IMX462, 2.1 MP	Sony IMX585, 8.3 MP
Pixel size	2.9 µm	2.9 µm
Pixel scale	2.39″/px	2.44″/px
Field of view	1.28° × 0.72°	2.60° × 1.46°
Sub exposures	10 s, 20 s, 30 s, 60 s	10 s, 20 s, 30 s
Dual-band filter	Built in (LP filter)	Clip-on option (Dual Band filter)
“No filter” position	UV/IR-cut	No filter
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	Vespera 3	Faster
Andromeda GalaxyGalaxy	1 h 27 min525 subs	1 h 24 min502 subs	Same
Orion NebulaEmission nebula	12 min75 subs	16 min98 subs	Seestar S50 1.3×
North America NebulaEmission nebula	1 h 25 min512 subs	2 h 09 min777 subs	Seestar S50 1.5×
Pinwheel GalaxyGalaxy	4 h 37 min1,661 subs	4 h 24 min1,586 subs	Same
Ring NebulaPlanetary nebula	7 min42 subs	7 min45 subs	Seestar S50 1.1×
Western Veil NebulaSupernova remnant	1 h 33 min557 subs	2 h 21 min849 subs	Seestar S50 1.5×
Hercules ClusterGlobular cluster	7 min44 subs	7 min43 subs	Same
PleiadesReflection nebula	2 h 42 min971 subs	2 h 35 min928 subs	Same

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	Vespera 3	Faster
Andromeda GalaxyGalaxy	34 min204 subs	32 min193 subs	Vespera 3 1.1×
Orion NebulaEmission nebula	10 min58 subs	7 min45 subs	Vespera 3 1.3×
North America NebulaEmission nebula	59 min357 subs	48 min290 subs	Vespera 3 1.2×
Pinwheel GalaxyGalaxy	1 h 40 min602 subs	1 h 35 min569 subs	Vespera 3 1.1×
Ring NebulaPlanetary nebula	6 min36 subs	5 min30 subs	Vespera 3 1.2×
Western Veil NebulaSupernova remnant	1 h 04 min387 subs	52 min315 subs	Vespera 3 1.2×
Hercules ClusterGlobular cluster	5 min30 subs	5 min30 subs	Same
PleiadesReflection nebula	1 h362 subs	57 min343 subs	Vespera 3 1.1×

Try the Seestar S50 in the calculator Try the Vespera 3

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 Vaonis Vespera 3

The 2026 Vespera: same 50 mm quadruplet class as the II on an 8 MP IMX585, with a 24 MP mosaic mode and 11 hours of battery. Per pixel it behaves like a Seestar S50 Pro without the built-in dual-band filter.

Where to buy the Vespera 3Vaonis store Direct Amazon UK Amazon USThe Vaonis 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 · Vespera 3 page