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

ZWO Seestar S50 Pro against Vaonis Vespera 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 Seestar S50 Pro 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 II is 1.2× faster, so the ranking flips under dark skies.

Field of view. Both frame 2.5° or so on the long side, so they suit the same targets.

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

Subs and dark skies. The Seestar S50 Pro goes up to 60 s subs in EQ mode, the Vespera 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 Vespera II does not, which costs it heavily on emission nebulae from any suburban sky.

Specifications side by side

Timed on the same targets

Suburban sky (Bortle 6)

Rural sky (Bortle 3)

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

About the Vaonis Vespera II

A 50 mm quadruplet on an 8 MP sensor with Vaonis’s mosaic mode for wide fields. Same optics class as the Seestar S50, four times the pixels.

Other comparisons

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