Seestar S30 vs DWARF II: which is faster for deep-sky imaging?

ZWO Seestar S30 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 S30 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 S30 is 3× faster.

Field of view. The DWARF II shows 3.19° × 1.79° against 2.13° × 1.20°, so big targets such as the Andromeda Galaxy, the North America Nebula and the Pleiades fit with room to spare where the Seestar S30 needs a mosaic or a tight crop.

Detail. The DWARF II samples at 2.99″ 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 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 S30 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 S30DWARF II
Aperture30 mm24 mm
Focal length150 mm (f/5.0)100 mm (f/4.2)
SensorSony IMX662, 2.1 MPSony IMX415, 8.3 MP
Pixel size2.9 µm1.45 µm
Pixel scale3.99″/px2.99″/px
Field of view2.13° × 1.20°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 used1.2 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 S30DWARF IIFaster
Andromeda GalaxyGalaxy1 h 32 min552 subs4 h 59 min1,198 subsSeestar S30 3×
Orion NebulaEmission nebula14 min84 subs57 min228 subsSeestar S30 4×
North America NebulaEmission nebula1 h 39 min597 subs7 h 45 min1,860 subsSeestar S30 5×
Pinwheel GalaxyGalaxy4 h 51 min1,748 subs16 h3,817 subsSeestar S30 3×
Ring NebulaPlanetary nebula7 min45 subs25 min101 subsSeestar S30 3×
Western Veil NebulaSupernova remnant1 h 48 min651 subs8 h 29 min2,035 subsSeestar S30 5×
Hercules ClusterGlobular cluster8 min46 subs24 min97 subsSeestar S30 3×
PleiadesReflection nebula2 h 50 min1,022 subs9 h 16 min2,225 subsSeestar S30 3×

Rural sky (Bortle 3)

Total integration for a solid image from a Bortle 3 sky, default subs, recommended filter for each scope.
TargetSeestar S30DWARF IIFaster
Andromeda GalaxyGalaxy38 min231 subs2 h 31 min603 subsSeestar S30 4×
Orion NebulaEmission nebula11 min67 subs31 min126 subsSeestar S30 2.8×
North America NebulaEmission nebula1 h 14 min442 subs3 h 50 min922 subsSeestar S30 3×
Pinwheel GalaxyGalaxy1 h 55 min689 subs7 h 44 min1,856 subsSeestar S30 4×
Ring NebulaPlanetary nebula6 min39 subs16 min64 subsSeestar S30 2.5×
Western Veil NebulaSupernova remnant1 h 20 min481 subs4 h 11 min1,006 subsSeestar S30 3×
Hercules ClusterGlobular cluster5 min30 subs14 min57 subsSeestar S30 2.8×
PleiadesReflection nebula1 h 09 min412 subs4 h 34 min1,097 subsSeestar S30 4×

Try the Seestar S30 in the calculator Try the DWARF II

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.

Where to buy the Seestar S30ZWO 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 S30

DWARF II

All comparisons · Buying guide · Seestar S30 page · DWARF II page