ZWO ASI294MC Pro Cooled Color Astronomy Camera

A one-shot color camera with large pixels and a 4/3-inch sensor for nebulae and galaxies

The ZWO ASI294MC Pro is a cooled one-shot-color astronomy camera built on Sony's back-illuminated 4/3-inch IMX294 sensor. It suits imagers stepping up from a DSLR or a small planetary camera who want color images of nebulae, galaxies and clusters without the extra gear of a mono setup. Two-stage cooling holds the sensor about 35°C below ambient, a 14-bit ADC gives about 13 stops of dynamic range, and a USB 3.0 connection with a 256MB DDR3 buffer keeps downloads reliable. The round red body is 78mm across.

Key specs: Sony IMX294 color sensor, 4/3-inch, 19.1 × 13.0mm · 11.7MP (4144 × 2822) · 4.63µm pixels · 14-bit ADC, about 13 stops dynamic range · 63.7ke⁻ full well · read noise as low as 1.2e⁻ · over 75% peak QE · two-stage cooling about 35°C below ambient · USB 3.0 with 256MB buffer and 2-port USB 2.0 hub

What you can image

• Large nebulae: the North America and Pelican, the Heart Nebula, the Rosette and the Orion Nebula with the Running Man. On a 250mm RedCat 51 the field is about 4.4° × 3.0° at 3.8″ per pixel.
• Galaxies and clusters: the Andromeda Galaxy's core and dust lanes, M81 and M82 together, and the Pleiades. On the 490mm ZWO FF70 the field is about 2.2° × 1.5° at 1.95″ per pixel.
• Smaller targets: the Whirlpool Galaxy, the Leo Triplet, the Eagle Nebula and the Dumbbell. On the 770mm FF110 the field is about 1.4° × 1.0° at 1.24″ per pixel.
• Emission nebulae from the city: with a dual-band filter, the Veil, the Crescent and the Soul Nebula from a light-polluted backyard.

How it works

A color filter over the sensor's pixels (a Bayer matrix) records red, green and blue in every frame, so stacking software turns your exposures straight into a color image. The camera connects to a computer or an ASIAIR Plus over USB 3.0 and needs 12V power to be recognized and to run its cooler (ZWO recommends 12V at 3–5A, 5.5 × 2.1mm plug, center positive, or an 11–15V lithium battery). Two USB 2.0 ports on the back can power a guide camera or electronic focuser, which keeps cables short at the scope.

The sensor sits 6.5mm behind the camera's front, or 17.5mm with the included 11mm T2 ring fitted. The included extenders bring that to the 55mm most flatteners and reducers expect, as ZWO's chart below shows, with or without an off-axis guider.

Using it in Colorado

• Front Range skies: a dual-band filter makes emission nebulae practical from Denver. Galaxies and reflection nebulae reward a drive to darker skies like Jackson Lake State Park or the Westcliffe area.
• Cold nights: the cooler holds a set temperature as the night cools off, so your dark frames keep matching your lights.

What to add for the best results

• 12V power (required): the ZWO 12V 5A adapter at home, or a PowerTank Lithium Pro in the field.
• ZWO UV/IR cut filter: the camera's window passes infrared, which bloats stars on most refractors. Use the 2" filter in a ZWO M42 2" filter drawer or the 1.25" one in the included nosepiece.
• ZWO Duo-Band filter or Optolong L-eXtreme: isolate hydrogen-alpha and OIII for emission nebulae under city lights or a bright Moon.
• ZWO OAG or a ZWO 30F5 guide scope with an ASI220MM Mini guide camera, for round stars in long exposures.
• ZWO EAFN electronic focuser: keeps focus sharp as the temperature drops.
• ASIAIR Plus: runs the camera, mount, guiding and focuser from your phone.
• A complete setup: the ZWO FF70 + AM3N bundle gives a 490mm refractor and a harmonic mount that suit this camera well.

ASI294MC Pro vs. ASI533MC Pro vs. ASI2600MC Pro vs. ASI294MM Pro

See all ZWO cooled deep-sky cameras.

What's in the box

• ASI294MC Pro camera body, front cover and camera bag
• T2-M48 extender (16.5mm), T2 extender (21mm) and M42-M48 adapter
• 1.25-inch nosepiece and T2-1.25" adapter
• Four spacers (0.1mm, two at 0.2mm and 0.5mm)
• USB 3.0 cable (2m) and two USB 2.0 cables (0.5m)
• Quick guide

The 12V power supply, filters and guide camera are sold separately.

ZWO ASI294MC Pro FAQ

Is the ASI294MC Pro good for beginners?

Yes, it's a sensible first cooled camera. One-shot color keeps the setup and processing simple, and its large pixels are forgiving on longer refractors. Start with an ASIAIR Plus to keep the learning curve short.

ASI294MC Pro or ASI2600MC Pro?

The ASI2600MC Pro covers about 1.5 times the area at 26MP, with a 16-bit ADC, no amp glow and a built-in IR-cut window, but needs a telescope that covers APS-C and costs about $500 more. The ASI294MC Pro is the better value if your scope's corrected field is smaller or your focal length is long.

Does it have amp glow?

A little, in the corners of long exposures, and stretched images can show a faint pattern. ZWO notes both are characteristics of this sensor and calibrate out with dark and flat frames taken at the same gain and temperature.

Do I need a UV/IR cut filter?

On refractors, yes. The camera's window is clear AR-coated glass, so infrared light reaches the sensor and can bloat stars. Reflectors and many astrographs with their own filter don't need one, and a dual-band filter already blocks infrared.

Can I use it for planets?

It can, and ZWO quotes 19 fps at full resolution, but a dedicated planetary camera with smaller pixels and faster frame rates does a better job. This camera is built for long deep-sky exposures.

What power and accessories do I need?

12V power (3–5A), a USB 3.0 port on a computer or an ASIAIR, a UV/IR cut filter for refractors, and a way to guide. The camera won't connect without 12V power, even with the cooler off.

Specifications