Seestar S30 vs eQuinox 2: which is faster for deep-sky imaging?

ZWO Seestar S30 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, they are about the same speed. From a rural Bortle 3 sky they are about the same speed.

Field of view. The Seestar S30 shows 2.13° × 1.20° 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 3.99″, so it pulls finer structure from small targets: planetary nebulae, globular cores, galaxy arms.

Subs and dark skies. The Seestar S30 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 S30 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

Timed on the same targets

Suburban sky (Bortle 6)

Rural sky (Bortle 3)

Try the Seestar S30 in the calculator Try the eQuinox 2

About the ZWO Seestar S30

Wider and lighter than the S50 with the same 2.9 µm pixels, so its per-pixel speed on extended targets is close despite the smaller aperture. Ideal for big nebulae.

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.

Other comparisons

All comparisons · Buying guide · Seestar S30 page · eQuinox 2 page