Buy the DwarfLab Dwarf 3 at $529 to $599 (529 to 599 € in Europe) for almost everyone, and the ZWO Seestar S50 at $499 (499 € in Europe) only if you can still find one. The criterion that actually decides is focal length against field: 250 mm and a tight 0.73° × 1.29° on the S50, versus 8.3 MP spread over 2.93° × 1.65° on the Dwarf 3.
The 20-second verdict
Buy the Seestar S50 if you want the best sampling under $500, the most mature software in the category after nearly three years of firmware updates, and a complete kit with carbon tripod, case and solar filter included. One commercial caveat matters: the S50 is out of stock on ZWO’s official site and listed as replaced by several retailers, though ZWO has not officially confirmed it is discontinued.
Buy the DwarfLab Dwarf 3 if you want four times the resolution at 8.3 MP, a field four times wider in area, 128 GB of storage and half the weight at 1.3 kg. Accept that no tripod is supplied and that EQ mode demands a second, equatorial tripod on top.
Side by side
| Spec | ZWO Seestar S50 | DwarfLab Dwarf 3 |
|---|---|---|
| Indicative price | $499 (499 € in Europe) | $529 to $599 (529 to 599 € in Europe) |
| Aperture | 50 mm | 35 mm |
| Focal length | 250 mm | 150 mm (737 mm equivalent) |
| Focal ratio | f/5 | f/4.3 |
| Sensor | Sony IMX462 | Sony IMX678 (Starvis 2) |
| Resolution | 2.1 MP | 8.3 MP |
| Field of view | 0.73° × 1.29° | 2.93° × 1.65° |
| Mount | Motorised alt-azimuth | Motorised alt-azimuth |
| Equatorial mode | Yes, via firmware, EQ tripod required | Yes, up to 60 s exposures, EQ tripod not included |
| Built-in filters | UV/IR-cut + Hα/OIII dual-band + dark, solar filter included | 3 switchable filters: VIS, Astro, Hα/OIII dual-band, solar included |
| Mosaic | Yes | Yes, 2×2 panorama |
| Battery life | 6 h | 5.5 h |
| Storage | 64 GB (eMMC) | 128 GB (eMMC) |
| Weight | 2.5 kg | 1.3 kg |
| Tripod included | Yes, carbon fibre | No |
What actually separates them
Optics and light gathering
50 mm against 35 mm is the clearest optical gap in this comparison. The S50 collects roughly twice the light of the Dwarf 3 and pairs it with 250 mm of focal length, the best sampling of this group. The Dwarf 3 replies with a faster f/4.3 against f/5, which shortens exposure for a given signal level, but a faster ratio does not create photons the aperture never gathered. On a faint galaxy or a small planetary nebula, the extra 15 mm of aperture is what shows. Winner on optics and light gathering: the Seestar S50.
Sensor, resolution and field
The Dwarf 3 turns the tables completely here. 8.3 MP on a Starvis 2 generation IMX678 against 2.1 MP on the older IMX462, and 2.93° × 1.65° against a 0.73° × 1.29° frame that is too tight for M31. The S50 also delivers its 2.1 MP in a vertical format that constrains composition. Where the S50 needs a mosaic, the Dwarf 3 shoots one frame and still has pixels left to crop. Winner on sensor, resolution and field: the Dwarf 3, and it is not close.
Battery, weight and portability
2.5 kg against 1.3 kg. The Dwarf 3 is under half the weight of the S50 and doubles the storage at 128 GB against 64 GB. The S50 keeps a 6 h battery against 5.5 h and, crucially, arrives with its carbon tripod and a case, so the packed kit is complete. But even with a tripod added, the Dwarf 3 stays the lighter bag. Winner on battery, weight and portability: the Dwarf 3, on raw mass.
Filters, software and real cost
Both include an Hα/OIII dual-band filter and a solar filter, and neither charges a subscription. The Dwarf 3 adds switchable VIS and Astro positions; the S50 answers with the most mature software ecosystem in the category and continuous updates. Real cost is where the picture turns: $499 (499 € in Europe) is the S50’s full bill, tripod and case included, while the Dwarf 3 opens at $529 (529 € in Europe) plus a tripod, plus an equatorial tripod for EQ mode. Both need an EQ tripod for equatorial work, so that cost is a wash. Winner on filters, software and real cost: the Seestar S50, on the condition that you find one in stock.
Which one for your use case
For beginners
The S50 asks nothing after purchase and its app is the most polished here, but a device with tight availability is a poor first buy if you need support and spares. The Dwarf 3 is freely available and simple, with a tripod to buy first. Winner for beginners: the Dwarf 3, on availability alone. If neither convinces, the ZWO Seestar S30 at $399 (399 € in Europe) is the safe entry point.
For large nebulae
0.73° × 1.29° is too tight for the Andromeda Galaxy or the widest emission nebulae, and mosaic mode is a workaround, not a fix. The Dwarf 3 covers 2.93° × 1.65° in one frame. Winner for large nebulae: the Dwarf 3, decisively.
For small targets and galaxies
250 mm of focal length over 50 mm of aperture is exactly what a small, faint target wants. The Dwarf 3’s 737 mm equivalent gives more pixels on target but over a smaller collecting area, so faint detail arrives more slowly. Winner for small targets and galaxies: the Seestar S50.
For city skies
Both carry an effective Hα/OIII dual-band filter, the S50’s being specifically noted as effective under polluted skies. The Dwarf 3 offers more filter positions, the S50 more aperture to push through the gradient. Winner for city skies: the Seestar S50, narrowly.
For travel
1.3 kg against 2.5 kg, and IP54 sealing on the Dwarf 3. Adding a light travel tripod still leaves the Dwarf 3 well under the S50’s packed weight. Winner for travel: the Dwarf 3.
Frequently asked questions
Is the Seestar S50 still available?
Availability is tight. It is out of stock on ZWO’s official site and several retailers list it as replaced, but ZWO has not officially confirmed that it is discontinued. Check stock before planning around it.
Dwarf 3 or Seestar: which resolves more detail?
The Dwarf 3 records more pixels at 8.3 MP against 2.1 MP. The S50 gathers more light with 50 mm against 35 mm and samples finer at 250 mm. On bright wide targets the Dwarf 3 wins; on faint small ones the S50 does.
What does the Dwarf 3 actually cost once set up?
Between $529 and $599 (529 to 599 € in Europe) for the body, plus a tripod, which is not supplied, plus an equatorial tripod if you want the 60 s exposures of EQ mode.
Do either of them need a subscription?
No. Both include every feature with no subscription.
Which other models should I compare?
Look at the Seestar S30 Pro and the Vaonis Vespera III, or browse all comparisons.