cameracomparison · 2-way
ZWO ASI178MM vs ZWO ASI120MC-S
ZWO
ASI178MM
A strong fit for photographers stepping into astro pairing with longer focal lengths where framing is tight.
ZWO
ASI120MC-S
A strong fit for photographers stepping into astro pairing with longer focal lengths where framing is tight.
Key differences
48% larger sensor
Finer pixels (2.4µm vs 3.75µm)
420% more resolution
Mono vs color
Specifications
| Specification | ZWO ASI178MM | ZWO ASI120MC-S |
|---|---|---|
| Sensor | ||
| Type | dedicated | guide-camera |
| Sensor | Sony IMX178 | AR0130CS |
| Sensor tech | CMOS | CMOS |
| Format | 1/1.8" | 1/3" |
| Sensor size | 7.4×4.9mm | 4.8×3.6mm |
| Diagonal | 8.9mm | 6.0mm |
| Pixel size | 2.40µm | 3.75µm |
| Resolution | 3096×2080 | 1280×960 |
| Megapixels | 6.4MP | 1.2MP |
| Color | No | Yes |
| Cooling | ||
| Cooled | No | No |
| Performance | ||
| Full well | 15000e⁻ | 13000e⁻ |
| Peak QE | 81% | 50% |
Advantages of ZWO ASI178MM
- Larger sensor (8.9mm vs 6mm diagonal) — wider field
- Finer sampling at 2.4µm pixels
- Higher resolution (6.4MP vs 1.23MP)
- Mono sensor — ideal for narrowband and LRGB
Advantages of ZWO ASI120MC-S
- Larger pixels — better low-light per-pixel sensitivity
- One-shot color — simpler workflow
Best for — ZWO ASI178MM
- Longer focal lengths — tighter framing on small targets
- Planetary and lunar high-resolution imaging
- Narrowband and LRGB workflows
Best for — ZWO ASI120MC-S
- Longer focal lengths — tighter framing on small targets
- Well-sampled deep-sky at medium focal lengths
- One-shot color — quick results, less processing
ZWO ASI178MM — typical FOV & scale
- On 250mm refractor (wide)FOV: 1.70° × 1.12°Scale: 1.98"/px
- On 800mm SCT reducerFOV: 0.53° × 0.35°Scale: 0.62"/px
- On 2000mm SCT nativeFOV: 0.21° × 0.14°Scale: 0.25"/px
ZWO ASI120MC-S — typical FOV & scale
- On 250mm refractor (wide)FOV: 1.10° × 0.83°Scale: 3.09"/px
- On 800mm SCT reducerFOV: 0.34° × 0.26°Scale: 0.97"/px
- On 2000mm SCT nativeFOV: 0.14° × 0.10°Scale: 0.39"/px
ZWO ASI178MM — recommended user
A strong fit for photographers stepping into astro pairing with longer focal lengths where framing is tight.
ZWO ASI120MC-S — recommended user
A strong fit for photographers stepping into astro pairing with longer focal lengths where framing is tight.