ZWO ASI 120MM Mini USB 2.0 Mono Camera
 ZWO ASI 120MM Mini USB 2.0 Mono CameraZWO ASI 120MM Mini USB 2.0 Mono Camera 

ZWO ASI 120MM Mini USB 2.0 Mono Camera

  (19 Reviews)
✓ 2 year warranty


42x in stock shipped 1-2 working days

About this product

Model:  zwo_asi120mm_mini
Part Number:  ASI120MINI

Compatible with the ZWO ASiair smiley

The ASI120MM Mini is a very capable guide camera that can handle most setups with ease, including most OAG configurations. 

Peak QE of 75% (better than the ICX618) and no Fixed-Pattern-Noise!  

Supports 35 FPS at it's maximum 1280 x 960 resolution and long time exposures up to 1000s!  

Compared to ICX618 based cameras the ZWO ASI120MM offers faster frame-rate, slightly higher sensitivity in visual light and more pixels for lunar imaging. 

The sensor is protected by an anti-reflection clear optical window. If imaging the Moon or planets we recommend fitting a 1.25" UV/IR rejection filter. 

The ASI120MM’s mono sensor can also be used with specialised UV or methane band filters, as well as infrared passing filters for lunar and planetary imaging (i.e. Baader IR-Pass, Red and Orange visual filters). IR-passing filters cut short wavelengths which prevents atmospheric dispersion softening the image. 

Note: The ASI120MM has a Micron sensor which might produce Newton Rings when used with solar telescopes. (Cameras fitted with Sony sensors are better in these circumstances).

Not recommended for use in Linux


  • 1.2 Megapixels, 1280 x 960 pixel 1/3" AR0130CS CMOS Mono Sensor
  • 3.75μm Square Pixels
  • 12bit ADC
  • Peak QE ~75%
  • 4.0e Read Noise, 13000e Full Well
  • ST4 Port
  • USB2.0 Type C
  • Weighs only 60g!


ZWO ASI120 cameras have have been reviewed at world most popular astronomy magazines. Please click links below to read PDF documents:

All ZWO cameras include a 2-year warranty. 

Camera Field of View Simulator

ASI120MM Mini Astrophotography Performance

The ASI120 mini camera offers very good performance for planetary imaging and guiding. Low read noise, high dynamic range, QE peak 75%, AR protective window and much more.

ASI120MM Mini QE Curve

Absolute QE Curve, we estimate the Peak Value is over 75%.

ASI120MM Mini vs ASI120MM-S

Compared with the ASI120MM-S camera, the ASI120mini is smaller, lighter weight, and it can reach focus at the same position as an eyepiece.

USB2.0 & ST4 Ports

USB 2.0 Port: The mini camera has one USB2.0 type C port. Type C is very popular in mobile phones and it is reversible so it doesn't matter which way around you insert the plug.

ST4 Port: To connect directly to a mounts auto guide port.

Connection Drawing

  1. M28.5-CS adapter
  2. CS-C adapter
  3. 1.25″ extender
  4. 1.25″ filter

Mechanical Drawing

What's in the box?

What's in the box

  • ASI120MM Mini Camera
  • 1.25" Cap
  • 0.5m USB2.0 Cable
  • 2m USB2.0 Cable
  • 2m ST-4 Cable
  • M28.5-CS Adapter
  • 1.25" Extender
  • Quick Guide


Sensor 1/3″ CMOS AR0130CS(Color)
Resolution 1.2Mega Pixels 1280×960
Pixel Size 3.75µm
Exposure Range 64µs-1000s
ROI Supported
ST4 Guider Port Yes
Focus Distance to Sensor 8.5mm
Shutter Type Rolling Shutter
Protect window AR coated window
Operating System Compatibility Mac, Windows, Linux
Interface USB2.0
Bit rate 12bit output(12bit ADC)
Adaptor 1.25″ / M28.5X0.6
Dimension φ36mm X 61mm
Weight 60g or 3.1 ounces (without lens)
Working Temperature -5°C—45°C
Storage Temperature -20°C—60°C
Working Relative Humidity 20%—80%
Storage Relative Humidity 20%—95%

Supported Resolutions:

Binning 1×1:

  • 1280X960@35FPS
  • 1280X720@46FPS
  • 1024X768@54FPS
  • 800X600@90FPS
  • 640X480@118FPS
  • 320X240@224FPS

Binning 2×2:

  • 640X480@35FPS

Additional resolutions can be user defined.

Downloads / Manuals

The following manuals and downloads are available for this product:


ZWO Software and Drivers


Customer reviews

Average Rating (19 Reviews):  
Write a Review and share your opinions!

Rating (max 5):  
Superb sensitivity
Friday, 17 June 2022  | 

I am using this camera with a small 50mm Orion guide scope (only 162mm focal length). Even with such a small scope, this is guiding my 6" Celestron scope on an AVX mount with excellent tracking. Any tracking errors are much smaller than any disturbances caused by seeing conditions so stars remain sharp on my DSLR even with 3 minute exposures (I could go as long as I want, but 3 mins is a suitable cutoff time for me). Sensitivity with this setup is amazing even with short (less than a second) exposures and never fails to find stars wherever I point the scope.

Rating (max 5):  
ZWO ASI 120MM Mini not just a guide camera.
Monday, 11 April 2022  | 

I have used one of these cameras as a guide camera and it is fine for this purpose. However I needed a low light sensitive camera to monitor the position of the scopes within the dome to ensure the aperture tracking was accurate. The ASI120 with a ZWO wide angle lens fitted running through SharpCap produces a crisp, zoomable image in near darkness, which can now be monitored remotely, given it is PC based. I notice ZWO now include right angled USB plugs, which put less strain on the connector. Thoroughly recommended.

Rating (max 5):  
Works perfectly with ASIAIR Plus
Thursday, 10 March 2022  | 

Great Service from FLO as usual and this camera works a treat when combined with my WO Guide scope. Connected to the ASIAIR plus (also ordered and fast delivery from FLO) via my ZWO 2600MC Pro on the USB2 Guide port, Iíve managed to focus and get star sizes right down. Sure there is the more sensitive guide camera but itís almost double the price - thereís really no need for the more sensitive version IMO as the 120 does a great job with a guide scope. Maybe Iíll get the more sensitive version if I go down the OAG route but Iíd be using that with a longer focal length OTA than I currently haveÖ Recommended for quality and service !

Rating (max 5):  
Very good for the price
Friday, 4 February 2022  | 

I have recently started astrophotography and initially I was taking photos without guiding and wasnít able to get above 40 second subs but with the guide camera, PHD and sharp cap my polar alignment is way better and I can now usually get around 5 minute exposures before trailing.

Rating (max 5):  
Quality piece of kit
Wednesday, 8 December 2021  | 

Having not had a chance to use this outside, I've only been able to set this up on the kitchen table to ensure it connects, which it does. It's fits very nicely into the William Optics 32mm Guide Scope . I'll update more as and when I'm able to test the tracking with PHD 2.
But, all in all, this seems like a well made piece of kit, worth the money. Recommended.

Rating (max 5):  
Top quality
Tuesday, 30 November 2021  | 

Perfect for what I need. It's solid, sensitive and as light as a feather. Thanks again to Chris for his help and expertise.

Rating (max 5):  
120mm mini
Tuesday, 9 November 2021  | 

Bought this to replace another camera which although worked well it just wasn't sensitive enough for guiding with, with 120mm I can get a few stars to lock on to so its worth it's weight in gold to me

Rating (max 5):  
Tuesday, 7 September 2021  | 

Purchased things after many reviews online and the 120mm is everything you want. Quality product, easy to set up and easy to use. The service and delivery time from First Light Optics was its usual high standard.

Rating (max 5):  
Very clean image - great for guiding
Thursday, 24 June 2021  | 

Arrived the day after ordering - FLO really excelled this time. I was a bit unsure how to set the camera up in INDI since my imaging camera is from ZWO too, but once I'd figured it out, it has worked flawlessly. But most importantly, the images produced are really low noise and it makes for a great guiding camera - PHD2 can pick out multiple stars for the multi-star guiding and I'm getting sub-arc second guiding on my AZ-EQ5GT / SharpStar 15028HNT on the first night out after just a quick calibration. I'll probably look to replace the guide camera on my obsy's EQ6R-Pro with an ASI120MM in the future. The only thing that would improve this camera would be the inclusion of a 1 1/4" parafocal ring so that you keep focus more easily after removing the camera for whatever reason, so I'll be getting one when they are back in stock.

Rating (max 5):  
You can't go wrong with this one
Thursday, 17 June 2021  | 

Great guide cam. It's simple and effective! It pairs well with my WO 32mm Uniguide scope.

Achieving focus is easy and can be done using the camera's native app. For first time use, I focused it during the day while holding the guide scope in my hand and read the graduated index on my guide scope. Using that as a beginning point, I was able to fine-tune the focus while mounted during the night. Now for daily use, I have the final reading on the guide scope, so I can quickly set it up.

Application support is great. Besides PHD2, I also use it with SharpCap Pro for polar alignment.

Service from FLO and their delivery partner was amazing. Ordered from India, and received on the 4th day!

Read all 19 customer reviews...


Please fill in the form below to ask a question.


Related Products
ZWO 1.25'' IR/UV Cut Filter
ZWO 1.25'' Helical Focuser