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

ZWO Seestar S50 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 2.0× 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 3× faster.

Field of view. Both frame 1.3° or so on the long side, so they suit the same targets.

Detail. The Origin Mark II samples at 1.23″ 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 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 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

Timed on the same targets

Suburban sky (Bortle 6)

Rural sky (Bortle 3)

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

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.

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.

Other comparisons

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