ZWO
ZWO ASI294MC Pro
A sensitive 4/3-inch cooled colour camera with big pixels and a deep full well, a versatile all-round deep-sky imager.
90/ 100
Camera Type
PlanetaryDeep sky
Built for deep sky, nebulae, galaxies and clusters under long exposure. Capable on the Moon, but oversized for high-resolution planets.
Type
One-shot colour
Cooling
−35°C
Pixel Size
4.63µm
Read noise
1.2 e⁻
Resolution
11.7 MP · 4144×2822
Sensor
Sony IMX294 · 4/3"
From$999
$100 above 90-day low
Price tracked by PolarisObserved 52 timesTracking since Jul 2026
The frame it captures
Same camera. Different telescope. A completely different photograph.
A camera has no field of view of its own, the telescope in front of it decides everything. Pick a target and watch the same 11.7-megapixel frame become three different images.
Framed with space to spare, the full disc and both companions.
Overflows the frame, the outer arms extend past the edges.
Only the bright core fits; the spiral arms spill off the sensor.
01What it's good at
What it's best at — and the trade-offs.
Best at
✓Large 4.63 µm pixels are very sensitive, ideal for fast scopes and faint targets.
✓A deep 66,000 e⁻ full well holds bright and faint detail in one frame.
✓A 4/3-inch field frames most nebulae and galaxies comfortably.
Trade-offs
!The IMX294 can show a faint amp-glow pattern that calibration must remove.
!Big pixels under-sample fine detail on long-focal-length scopes.
!One-shot colour trails mono for narrowband from bad skies.
02In plain English
The numbers, in plain English.
Read noiseExcellent
1.2 e⁻
The camera adds barely more than one electron of its own noise per readout, so faint signal survives in short subframes. That suits imperfect skies, where shorter exposures mean fewer frames ruined by wind, cloud or a passing satellite.
Pixel sizeLarge
4.63 µm
Larger pixels each collect more light, which shortens the exposure needed to reach a given signal level. The trade is coarser sampling, so this sensor suits shorter focal lengths and average seeing rather than long, high-resolution setups.
SensorMid-size
Sony IMX294, 4/3 inch
Between a 1 inch chip and APS-C, which frames most nebulae comfortably at 400 to 800 mm without demanding perfect corner correction from the telescope. A practical middle ground for a first cooled camera.
CoolingRegulated TEC
35 C below ambient
Deep regulated cooling drops thermal noise sharply and keeps the sensor at a repeatable temperature, so dark frames taken one night remain valid the next. That repeatability is what turns calibration from a chore into a library.
Full wellDynamic range
66,000 e⁻
An unusually deep well for this class, so bright stars and nebula cores hold their detail rather than clipping to white while you expose for the faint material around them.
Peak QESensitivity
About 90 percent
Nine tenths of the arriving photons are recorded, so very little of what the telescope gathers is thrown away. Combined with the large pixels, this is a fast camera in practice, not just on paper.
03Typical targets
What it shines on.
04Build your imaging rig
Everything you'd actually buy.
Capture
The scope that forms the image
Sky-Watcher Esprit 100EDX
550 mm f/5.5 apo, a flat, fast field that suits this sensor.
Track
What holds it steady
A tracking equatorial mount
Long exposures need a solid, guided EQ mount underneath.
Complete it
What unlocks its range
A light-pollution or dual-band filter
Lifts nebula contrast from the suburbs on a one-shot colour sensor.
02The Polaris Score
How it scores, and why.
90/ 100
ZWO ASI294MC Pro
#1 of 7 colour deep-sky cameras
High sensitivity, a generous full well and a mid-size field make it a genuinely versatile deep-sky camera that punches above its price.
Image quality91
Low-light sensitivity93
Ease of use90
Value90
Polaris weighs how well the camera does the job it was designed for — image quality, sensitivity, versatility and value — never list price or brand.
03Who it's for
An honest fit check.
Buy it if you
✓Image deep-sky targets: nebulae, galaxies and clusters.
✓Want cooled, low-noise colour data without the complexity of mono and filters.
✓Own or plan a short-to-medium apo refractor or fast reflector.
✓Value a one-shot-colour workflow that gets to a finished image quickly.
Look elsewhere if you
!Mainly image planets or the Moon (a small fast camera wins there).
!Want the absolute deepest narrowband detail (go mono with filters).
!Have no tracking mount, long exposures need one.
!Need the widest possible field on a full-frame sensor.
05The numbers
Full specifications.
Sensor
ModelSony IMX294
TypeCMOS · 4/3"
Megapixels11.7
Pixel Size4.63µm
Bit depth14-bit ADC
Noise & sensitivity
Read noise1.2 e⁻
Full well66,000 e⁻
Peak QE~90%
Dynamic range14 stops
Cooling
Cooling−35°C
Connectivity & fit
InterfaceUSB 3.0
Weight0.41 kg
More
cooledtrue
Sensor Height13.0mm
Sensor Width19.1mm
Editor’s Take
The 4.63 µm pixels drink light, so faint nebulosity comes up fast even on modest scopes. It sits in a sweet spot between the small 533 and the large 2600.
— The Skynocular verdict
06Alternatives