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ZWO ASI120MM-S Mono 1/3 CMOS USB3.0 Camera with Autoguider Port

ZWO ASI120MM-S Mono 1/3 CMOS USB3.0 Camera with Autoguider Port


The ZWO ASI120MM-S Mono 1/3 CMOS USB3.0 Camera is an affordable and capable guide, planetary and basic deep sky camera.
Price includes UK delivery!


The ZWO ASI120MM-S Monochrome 1/3 CMOS USB3.0 Camera with Autoguider Port is an excellent choice for an affordable planetary and deep sky camera for those who have just started in astro photography and cannot to spend a fortune on a specialist Astro photography camera or want to replace a modified webcam or a cheaper planetary imager.
This NEW version also comes with an AUTOGUIDER PORT so you may now use it both for imaging or guiding!

With the ZWO ASI120MM-S camera you can achieve better results than with those beginner cameras. We are not saying that anything is wrong with those cameras like the TSSI or Scopiumcam, but this is just simply better for a still affordable price.
If you however want the ultimate camera, go for a Moravian Instruments camera that you may also find on our website, but of course for more bucks.
Basically, as the old saying says, you get what you pay for…

According to customer feedback, these cameras worth every penny invested.
Mostly used for planetary imaging, it can also be used for deep sky imaging up to a certain level. This monochrome version is recommended for L-RGB or narrow band deep sky photography if you want to get out the best data from your camera and achieve sharp, contrasty deep sky images or planetary images, but if you don’t want the hassle or cannot spend much time and happy to go for a compromise, simply choose the colour version, the ZWO ASI120MC.
With this monochrome version, you’ll also need a filter wheel and a set of L-RGB filters or H-alpha and OIII filters, and maybe even H-beta and SII filters as well for narrow band astro photography…)

Features of the ZWO ASI120MM-S
Recommended for the Sun, Moon and some deep sky objects
(To image the Sun you’ll have to use a proper front solar filter or Herschel wedge depending on your telescope. Please contact us if not sure!)
Resolution: 1280X960 at up to 30fps
Long time exposure up to 1000s!
NEW – Autoguider Port
Built-in RAW mode and Grey mode output support. Only about 30% storage space required compared to the Color data format!
Peak Quantum Efficiency: 75% (better than ICX618)
No fixed pattern noise (FPN)!
Full aluminum housing with standard 2″ interface
M42X0.75 internal thread.
Image courtesy of Scott Anttia.


  • ASI120MM-S monochrome camera
  • ST4 cable
  • USB cable
  • 150-degree lens
  • 1.25″ nosepiece with male T-thread
  • 1.25″ end cap for above nosepiece
  • CD (with instructions, drivers and software, although we recommend to download the latest versions online)


On the included CD you’ll find drivers and two software applications: Firecapture and SharpCap. These are both freeware and the latest versions can be downloaded from the developers’ websites.
If you have any problem with installing any of the software from the CD, please download them from here:
Firecapture Downloads
SharpCap Downloads

We’d recommend to use the beta version of Firecapture as the 2.2 version is not fully functional with the ZWO ASI cameras…

to use the ASI camera under Mac there are 2 steps to do:
1. install Parrallel virtual machine.
2. flash the ASI firmware.

Here is a link to the update tool for ASI120 (ONLY FOR mac USERS!):
(Please don’t upgrade your firmware if you use a PC.)
Update is very easy, you just need to run the tool on a machine which runs the camera…


Here you can download a pdf file that will guide you through ZWO ASI camera troubleshooting. Click here!


Please find further info about autoguiding with this camera here: ZWO ASI120 AUTOGUIDING

150 degree wide lens included! You don’t even need a telescope to start imaging the stars!


Image courtesy of Scott Anttia.

Specification of ZWO ASI120MM-S

Sensor: 1/3″ CMOS MT9M034 (mono)
Resolution: 1.2Mega Pixels 1280×960
Pixel Size: 3.75µm
Exposure Rage: 64µs-1000s

ROI: Supported
Interface: USB3.0
Bit rate: 12bit output(12bit ADC)
Adaptor: 2″ / 1.25″ / M42X0.75
Dimension: φ62mm X 28mm
Weight: 100g

Working Temperature: -5°C—45°C
Storage Temperature: -20°C—60°C
Working Relative Humidity: 20%—80%
Storage Relative Humidity: 20%—95%

Transmission chart of the Clear filter used as an optical window in the ZWO ASI120MM and ZWO 130MM CMOS cameras

For full specification, driver installation tutorial (youtube video), basic usage information and recommended third party software please visit the manufacturer’s website: ZWOptical

There is also a Yahoo Group where you can find lots of information about how other members use the ZWO cameras: Yahoo Group ZWO ASI Cameras

See an article in our blog about
How to deal with Newton’s rings in CMOS imaging?

Below is an example of a planetary imaging setup with a Imaging Flip Mirror, ZWO Filter Wheel and ZWO ASI120MM monochrome camera. With the help of a Variable Locking T2 Extension we could achieve parfocality.  The eyepiece holder (that is part of the Imaging Flip Mirror) is also adjustable, so with these two adjastable items we can achieve various positions of the eyepiece thus parfocality can be achieved with eyepieces of various focal lengths. To see approximately the same field, you’d have to use an eyepiece with approximately 6mm focal length. Please note that this setup might not work for a Newtonian telescope due to the long back focus requirement.


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