How Many Subs

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

ZWO Seestar S50 Pro against Vaonis Vespera Pro 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 Pro is 2.4× 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 Pro is 1.8× faster.

Field of view. The Seestar S50 Pro shows 2.45° × 1.38° against 1.65° × 1.65°, so big targets such as the Andromeda Galaxy, the North America Nebula and the Pleiades fit with room to spare where the Vespera Pro 2 needs a mosaic or a tight crop.

Detail. The Vespera Pro 2 samples at 1.68″ 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 Vespera Pro 2 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 Vespera Pro 2 does not, which costs it heavily on emission nebulae from any suburban sky.

Specifications side by side

SpecSeestar S50 ProVespera Pro 2
Aperture50 mm50 mm
Focal length260 mm (f/5.2)245 mm (f/4.9)
SensorOmniVision OS08B10 (1/1.2″), 8.3 MPSony IMX676, 12.5 MP
Pixel size2.9 µm2 µm
Pixel scale2.30″/px1.68″/px
Field of view2.45° × 1.38°1.65° × 1.65°
Sub exposures10 s, 20 s, 30 s, 60 s10 s, 20 s, 30 s
Dual-band filterBuilt in (LP filter)Clip-on option (Dual Band filter)
“No filter” positionUV/IR-cutNo filter
Read noise used1 e⁻0.8 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.
TargetSeestar S50 ProVespera Pro 2Faster
Andromeda GalaxyGalaxy1 h 36 min575 subs3 h 07 min1,121 subsSeestar S50 Pro 2.0×
Orion NebulaEmission nebula14 min83 subs36 min217 subsSeestar S50 Pro 2.6×
North America NebulaEmission nebula1 h 36 min574 subs4 h 49 min1,736 subsSeestar S50 Pro 3×
Pinwheel GalaxyGalaxy5 h 03 min1,817 subs9 h 52 min3,552 subsSeestar S50 Pro 2.0×
Ring NebulaPlanetary nebula8 min46 subs16 min99 subsSeestar S50 Pro 2.2×
Western Veil NebulaSupernova remnant1 h 44 min625 subs5 h 16 min1,898 subsSeestar S50 Pro 3×
Hercules ClusterGlobular cluster8 min48 subs15 min93 subsSeestar S50 Pro 1.9×
PleiadesReflection nebula2 h 57 min1,063 subs5 h 46 min2,075 subsSeestar S50 Pro 2.0×

Rural sky (Bortle 3)

Total integration for a solid image from a Bortle 3 sky, default subs, recommended filter for each scope.
TargetSeestar S50 ProVespera Pro 2Faster
Andromeda GalaxyGalaxy38 min227 subs1 h 19 min472 subsSeestar S50 Pro 2.1×
Orion NebulaEmission nebula11 min65 subs17 min105 subsSeestar S50 Pro 1.6×
North America NebulaEmission nebula1 h 08 min407 subs1 h 59 min713 subsSeestar S50 Pro 1.8×
Pinwheel GalaxyGalaxy1 h 52 min672 subs3 h 56 min1,414 subsSeestar S50 Pro 2.1×
Ring NebulaPlanetary nebula7 min40 subs10 min59 subsSeestar S50 Pro 1.5×
Western Veil NebulaSupernova remnant1 h 13 min441 subs2 h 09 min776 subsSeestar S50 Pro 1.8×
Hercules ClusterGlobular cluster5 min30 subs8 min50 subsSeestar S50 Pro 1.6×
PleiadesReflection nebula1 h 07 min404 subs2 h 21 min845 subsSeestar S50 Pro 2.1×

Try the Seestar S50 Pro in the calculator Try the Vespera Pro 2

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 DirectAmazon UKAmazon 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 Pro 2

The square-sensor 2026 Vespera with 2 µm pixels. Sharper than the Vespera 3 on small targets and correspondingly slower per pixel; the 12.5 MP square frame suits galaxies and planetaries.

Where to buy the Vespera Pro 2Vaonis store DirectAmazon UKAmazon 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

Seestar S50 Pro

Vespera Pro 2

All comparisons · Buying guide · Seestar S50 Pro page · Vespera Pro 2 page