Best Guide Cameras (October 2026)
A guide camera does one boring job, over and over: it watches a single star and tells your mount when it drifts. When it does that job well you never think about it, and when it doesn’t you throw away half a night of subs to egg-shaped stars. The good news is that the choice is easier than it used to be, because the field has settled on a handful of sensors that work.
Two things decide which camera fits your rig. The first is where it sits. Behind a small 30 mm guide scope almost any modern mono sensor will find a star, but behind an off-axis guider (OAG) the camera sees only a sliver of the field through a small prism, so a bigger, more sensitive sensor pays off. The second is pixel size relative to your guide focal length; you want enough resolution for the guiding software to measure sub-pixel movement, without pixels so tiny that faint stars disappear into noise.
The picks below run from cheap starter guiders to all-in-one cameras that guide from inside the imaging camera itself. One housekeeping note: the ASI290MM Mini, a favourite for years, is discontinued, and ZWO points buyers to the ASI220MM Mini instead.
ZWO ASI120MM Mini
The ASI120MM Mini is still the cheapest sensible way into autoguiding. Its sensor is small and older than everything else on this list, but behind a short guide scope it finds stars without fuss, plugs straight into an ASIAIR or PHD2, and costs little enough that nobody regrets buying it. If you’re shooting at a few hundred millimetres of focal length with a 30 mm guide scope, it’s enough. Once you move to an OAG or a long-focal-length scope, you’ll outgrow it.
ZWO ASI220MM Mini
This is the default recommendation in late 2026, and for good reason. The IMX220 sensor has 4 µm pixels, very low read noise and high quantum efficiency, which means it locks onto faint guide stars that the ASI120MM Mini simply misses. ZWO positions it as the successor to both the 120MM and the 290MM Minis. It works on a guide scope and on a standard OAG with an 8×8 mm prism, so it’s the one camera that covers most setups at a mid-range price.
ZWO ASI174MM Mini
ZWO calls the ASI174MM Mini its top-end guide camera, and its big 1/1.2-inch sensor with 5.86 µm pixels explains why: through an OAG it sees far more sky than smaller guiders, so you rarely have to rotate the prism hunting for a star. Pair it with a large-prism OAG such as the ZWO OAG-L or a QHY OAG; on the standard small-prism ZWO OAG, users report heavy vignetting. It’s the right pick for long-focal-length SCTs and RCs where guide stars are scarce.
QHY5III585M
QHY’s 5III series exists for guiding, and the 585M puts the large IMX585 sensor in that small body. The 2.9 µm pixels and wide sensor suit OAG guiding on scopes with medium focal lengths, and an ST-4 port is there if your mount still wants it. It also doubles as a capable mono planetary camera, so it earns its place in the bag on nights when you’re not shooting deep sky.
QHY5III174M
This is QHY’s take on the same IMX174 sensor that sits in the ASI174MM Mini, so it offers the same large field and big pixels for finding stars through an off-axis guider. It’s a good fit if you already run QHY cameras and filter wheels and would rather keep the whole imaging train under one brand’s drivers. It sits at the upper end of the price range for a dedicated guider.
QHY5III200M
The 5III200M is a mid-priced guider with 4 µm pixels and strong near-infrared sensitivity, which helps when you guide through narrowband filters or in hazy skies where blue light fades first. It’s a reasonable alternative to the ASI220MM Mini for QHY users who want a guider that matches their main camera’s software.
ZWO ASI2600MM Air
The Air series takes a different route: it builds a small guide sensor and an ASIAIR controller into the cooled imaging camera. The guide sensor looks through your main telescope, so there’s no guide scope, no OAG and no differential flexure to chase. It’s a premium purchase and your optics have to illuminate the camera’s full APS-C sensor, but for anyone building a new rig from scratch it removes a whole layer of cables and brackets.
Conclusion
For a short refractor with a 30 mm guide scope, the ASI120MM Mini still does the job, and the ASI220MM Mini is worth the small step up for anyone who wants to stop hunting for guide stars. If you guide through an off-axis guider on a longer scope, put your money into a bigger sensor: the ASI174MM Mini, QHY5III174M or QHY5III585M, matched to an OAG with a large prism. And if you’re replacing your main camera anyway, the ASI2600MM Air makes the separate guide camera disappear altogether.