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

ZWO Seestar S50 Pro against DwarfLab DWARF 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 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 3× faster.

Field of view. The DWARF II shows 3.19° × 1.79° against 2.45° × 1.38°, so big targets such as the Andromeda Galaxy, the North America Nebula and the Pleiades fit with room to spare where the Seestar S50 Pro needs a mosaic or a tight crop.

Detail. The Seestar S50 Pro samples at 2.30″ per pixel against 2.99″, 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 DWARF II tops out at 15 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 DWARF II does not, which costs it heavily on emission nebulae from any suburban sky.

Specifications side by side

SpecSeestar S50 ProDWARF II
Aperture50 mm24 mm
Focal length260 mm (f/5.2)100 mm (f/4.2)
SensorOmniVision OS08B10 (1/1.2″), 8.3 MPSony IMX415, 8.3 MP
Pixel size2.9 µm1.45 µm
Pixel scale2.30″/px2.99″/px
Field of view2.45° × 1.38°3.19° × 1.79°
Sub exposures10 s, 20 s, 30 s, 60 s15 s
Dual-band filterBuilt in (LP filter)None
“No filter” positionUV/IR-cutAstro
Read noise used1 e⁻1.2 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 ProDWARF IIFaster
Andromeda GalaxyGalaxy1 h 36 min575 subs4 h 59 min1,198 subsSeestar S50 Pro 3×
Orion NebulaEmission nebula14 min83 subs57 min228 subsSeestar S50 Pro 4×
North America NebulaEmission nebula1 h 36 min574 subs7 h 45 min1,860 subsSeestar S50 Pro 5×
Pinwheel GalaxyGalaxy5 h 03 min1,817 subs16 h3,817 subsSeestar S50 Pro 3×
Ring NebulaPlanetary nebula8 min46 subs25 min101 subsSeestar S50 Pro 3×
Western Veil NebulaSupernova remnant1 h 44 min625 subs8 h 29 min2,035 subsSeestar S50 Pro 5×
Hercules ClusterGlobular cluster8 min48 subs24 min97 subsSeestar S50 Pro 3×
PleiadesReflection nebula2 h 57 min1,063 subs9 h 16 min2,225 subsSeestar S50 Pro 3×

Rural sky (Bortle 3)

Total integration for a solid image from a Bortle 3 sky, default subs, recommended filter for each scope.
TargetSeestar S50 ProDWARF IIFaster
Andromeda GalaxyGalaxy38 min227 subs2 h 31 min603 subsSeestar S50 Pro 4×
Orion NebulaEmission nebula11 min65 subs31 min126 subsSeestar S50 Pro 2.9×
North America NebulaEmission nebula1 h 08 min407 subs3 h 50 min922 subsSeestar S50 Pro 3×
Pinwheel GalaxyGalaxy1 h 52 min672 subs7 h 44 min1,856 subsSeestar S50 Pro 4×
Ring NebulaPlanetary nebula7 min40 subs16 min64 subsSeestar S50 Pro 2.4×
Western Veil NebulaSupernova remnant1 h 13 min441 subs4 h 11 min1,006 subsSeestar S50 Pro 3×
Hercules ClusterGlobular cluster5 min30 subs14 min57 subsSeestar S50 Pro 2.8×
PleiadesReflection nebula1 h 07 min404 subs4 h 34 min1,097 subsSeestar S50 Pro 4×

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

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 DwarfLab DWARF II

The original pocket scope. 24 mm aperture and tiny 1.45 µm pixels mean it is slow per pixel, so bin or downsample and be patient.

Where to buy the DWARF IIAmazon UKAmazon USAffiliate links: As an Amazon Associate I earn from qualifying purchases, at no cost to you.

Other comparisons

Seestar S50 Pro

DWARF II

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