ZWO ASI290MM Mini CMOS Telescope Guide Camera

  • ZWO ASI290MM Mini is one of the best-selling guide cameras in the industry.
  • Doubles as a planetary camera.
  • Pixel Array: 1936 x 1096.
  • Pixel Size: 2.9 Micrometers.
  • Read Noise: 1.0 e.
  • Peak QE: 80%.
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  • Regular price $299.00

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ZWO ASI290MM Mini CMOS Telescope Guide Camera

A Go-To for Guiding and More

The ZWO ASI290MM Mini is a top-notch monochrome guide camera, well suited for both planetary imaging and acting as a guider to amplify the usefulness of other astronomy instruments. Despite being qualified as a 'miniature' camera, it still operates at a high level of performance.

A Powerhouse in a Small Package

With a peak QE over 80%, a read noise of only 1.0 e, a pixel array of 1936 x 1096, and a pixel size of only 2.9 micrometers, it qualifies as a powerhouse despite its small size. It achieves all of this while presenting a small and slender profile, taking up a minimum of space in your imaging train. 

ZWO ASI290MM Mini Specifications at a Glance


USB 2.0 Port: Its Type C port is very popular in mobile phones.

ST4 Port: Can connect the mini camera directly to the autoguider port of the mount.


ADC12 bit
Back Focus8.5 mm
Camera ConnectionM28.5x0.6 / Type C mount
Color or MonoMonochrome
Delta T45C
Dynamic Range12 Stops
Free ShippingYes
Full Rez Frame Rate20.4fps
Full Well14.6ke
Max Frame Rate355.9fps
Mega Pixels2.1 mp
MP2 to 4 MP
Peak QE78%
Pixel Array1936 x 1096
Pixel Size2.9 microns
PS3 Microns or Smaller
QE Peak80%
Read Noise3.1e
Sensor Diagonal6.5 mm
Sensor TypeCMOS
SensorSony IMX290
Warranty2 Year Warranty
Weight0.1322 lbs


  • Camera Body.
  • 1.25-inch Cover.
  • User Manual.
  • Software CD ROM.
  • 0.5 m USB 2.0 Cable.
  • 2 m USB 2.0 Cable.
  • ST4 Cable.
  • M28.5-CS Adapter.
  • 1.25-inch Extender.
Customer Reviews
4.6 Based on 16 Reviews
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Steven P.
United States United States
nice guide camera

I bought this because the very short backfocus requirement makes it a good fit to go with the ASI1600mm, 1.25" filter wheel and OAG. The 1600 has even less back focus which allows it to work with the small filters, so to avoid needing spacers between the filter wheel and the OAG you need something like this camera. It came right up and seems quite sensitive. Also works well with PHD. No negatives to report.

Joseph D.
United States United States
Great guide cam with one flaw

Upon opening this guide cam, I noticed the female extension tube (or male mating ring on camera, hard to tell which) appears to have stripped threads. The camera extension is almost useless as it doesn't hold tightly to the camera and allows it to flop around. I emailed to Opt support just after I discovered this and sent pictures of the pieces that are the problem, but received no response. I guess I'm on my own to figure out a solution. I'd give the camera itself 5 stars, but broken extension right out of the box and no support from Opt drops it down to 3 stars.

Cesar C.
United States United States
ZWO 290

Excellent experience. Great guide cam.

United States United States
Fantastic ASI290MM

It worked flawlessly with my ASIAIR.

United States United States

This camera is fine, expensive for a guide-camera, but fine - UNLESS - you’re using it on an ZWO OAG and the AsiAir. Why? Say you decided you need this camera for more sensitivity and the mini fit for your ZWO OAG to work. You want the OAG cuz it’s the thing to use for auto-guiding your long 2032mm FL Celestron SCT which is what OAGs are for. You set up everything and find it won’t work; can’t find stars, the one’s you find are just a boiling mess of light that the AsiAir can’t guide on. Why? Cuz with a long FL like 2032mm your image scale is less then .3” with that 2.9 micron pixel size and the oversampling is just showing you how bad seeing conditions are. Can’t find stars? Your FOV is only about 10’ x 5’ and the speed of your telescope is only F/10 or so coming through that tiny prism in the OAG. Go to a reducer? Why did you buy that long FL then? What’s the work-around? If you could bin that should help a lot, but the 290mm only provides 2x2 binning and the AsiAir auto-guider won’t let you change binning on the guide-camera at all. To make it work try PhD which will change the binning, or reconsider your whole auto-guiding paradigm. If you go back to a traditional guide scope you probably don’t need to spend this much money on the asi290mm guide camera. What it boils own to is you need to match the pixel size to the guiding focal length to be sure it works. This camera might not be the choice for you.

United States United States
ZWO ASI290MM Mini CMOS Telescope Guide Camera

It was the easiest thing to set up on my scope.i love the images and i'am using it for a guide camera . i like the idea of its size ,quality and weight.