ZWO ASI220MM Mini Monochrome Guide Camera

A guide camera that finds a guide star almost anywhere

The ZWO ASI220MM Mini is a monochrome guide camera that keeps your mount on target during long astrophotography exposures. It watches a star through a guide scope or off-axis guider and tells the mount how to correct its tracking many times a minute, so your stars stay round. It uses a 1/1.8" SC2210 sensor with 4µm pixels and a peak QE of about 92%, and it weighs just 60g (2.1oz).

Key specs: 1/1.8" SC2210 mono sensor (7.68 x 4.32mm) · 1920 x 1080, 4µm pixels · read noise 0.6e · QE about 92% · 12-bit ADC · USB-C (USB 2.0) and ST4 · 1.25" barrel · 60g

What it does for your images

• Round stars in long exposures: guiding corrects small tracking errors so you can expose for minutes instead of seconds.
• Dithering: with the ASIAIR or PHD2, the guider shifts the frame slightly between exposures, which removes walking noise from stacked images.
• Faster polar alignment: the ASIAIR and PHD2 can use the guide camera for polar alignment routines.
• Works with an off-axis guider: the larger sensor helps find stars in the small field of an OAG on a long focal length telescope.

How to set it up

Slide the camera into your guide scope's 1.25" focuser, focus on a star, and connect the USB-C cable to your ASIAIR or computer. In the ASIAIR app or PHD2, calibrate once and start guiding. If your mount has an ST4 autoguider port, the included ST4 cable can send corrections directly, though most setups now guide over the mount's USB connection.

With the ZWO 30F5 (150mm focal length), the ASI220MM Mini sees a 2.9° x 1.6° field at about 5.5 arcseconds per pixel, a comfortable match for most refractor imaging setups.

What to add for the best results

• ZWO 30F5 Mini Guide Scope (or another guide scope or off-axis guider, required): the camera needs optics to look through.
• ZWO ASIAIR Plus 256GB: runs guiding, your main camera and the mount from your phone.
• ZWO Large OAG off-axis guider: for SCTs and long refractors where a separate guide scope can flex.
• William Optics UniGuide 32: a slide-base guide scope for William Optics refractors with a slide-base handle.

ASI220MM Mini vs. other ZWO guide cameras

See all ZWO guide cameras and autoguiding gear.

What's in the box

• ASI220MM Mini camera
• 1.25" cover
• 1.25" extender
• M28.5 to CS adapter
• ST4 guide cable
• USB 2.0 Type-C cables, 0.5m and 2m
• Quick guide

The guide scope or off-axis guider is sold separately.

ZWO ASI220MM Mini FAQ

Is it good for beginners?

Yes. Guiding sounds technical, but with an ASIAIR it's a few taps: focus the guide camera once, calibrate, and start. It's usually the second upgrade we suggest after a tracking mount and imaging camera.

ASI220MM Mini or ASI120MM Mini?

The ASI220MM Mini has nearly twice the sensor area and lower read noise, so it finds guide stars more easily, especially with an OAG. The ASI120MM Mini still works well in a guide scope if you're on a tight budget.

Which guide scope should I use?

For refractors and small SCTs, a 30mm to 50mm guide scope with 120mm to 200mm focal length works well, such as the ZWO 30F5. For long SCTs, an off-axis guider avoids flexure between the guide scope and main telescope.

Does it work with the ASIAIR?

Yes. Plug it into one of the ASIAIR's USB ports and select it as the guide camera.

Can I use it as an imaging camera?

It's designed for guiding. For deep-sky images, pair it with a dedicated cooled imaging camera such as the ASI2600MC Pro.

Specifications