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IMPORTANT: Our store is located in Canada. All orders that include products manufactured outside of Canada or USA will be subject to tariffs and duties, regardless of the order value. US customers are responsible for all applicable duties and tariffs, and those will be billed by the carrier, except for the Lacerta upgrade kit, for which we collect them at checkout.
ZWO ASI120MM Mini Mono Guide Camera
ZWO ASI120MM Mini Mono Guide Camera
ZWO ASI120MM Mini Mono Guide Camera
ZWO ASI120MM Mini Mono Guide Camera
ZWO ASI120MM Mini Mono Guide Camera

ZWO ASI120MM Mini Mono Guide Camera

by ZWO
SKU ZWO-ASI120MINI
$149.00 - $149.00
$149.00
$149.00 - $149.00
$149.00
Price Match Policy!
  • 1.2 Megapixel monochrome CMOS sensor (1280 x 960)
  • 3.75µm pixel size for precise guiding and planetary detail
  • Peak Quantum Efficiency of 80% for high sensitivity
  • Lightweight 0.2 lb, 1.25" eyepiece form factor
  • Integrated ST-4 and USB 2.0 ports
5 in stock
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  • Description
  • FAQ
  • Specifications
  • In the Box
  • Downloads
  • Warranty

  • ZWO ASI120MM Mini Monochrome Astronomy Camera

    The ZWO ASI120MM Mini combines a sensitive 1.2 MP monochrome sensor with 3.75µm pixels, making it a definitive choice for autoguiding and entry-level planetary imaging. Its peak Quantum Efficiency of 80% and low 4.0e read noise ensure faint guide stars are reliably detected in short exposures. Capturing data through its 12-bit ADC at up to 35 FPS, the ASI120MM Mini delivers smooth, high-contrast video of the Moon and planets.

    Reliable Guiding with 80% Peak QE

    A guide camera's primary job is to detect stars, and the ASI120MM Mini's monochrome sensor does this with high efficiency. With a peak QE of 80%, the ON Semiconductor AR0130CS sensor gathers a high percentage of incoming photons, allowing you to use shorter guide exposures and track fainter stars. Combined with a low 4.0e read noise, the camera produces a clean signal-to-noise ratio, preventing your guiding software from losing the star and ruining a long-exposure sub.

    Planetary and Lunar Imaging at up to 224 FPS

    While designed for guiding, the ASI120MM Mini is a capable planetary imager. The 1280 x 960 sensor is an excellent match for capturing the full disk of Jupiter or Saturn with most long focal length telescopes. For higher-magnification work, you can use a smaller region of interest (ROI) to dramatically increase the frame rate—capturing at 118 FPS at 640x480 resolution allows you to freeze moments of steady seeing, a technique known as "lucky imaging." The camera's USB 2.0 interface provides ample speed for this purpose, simplifying cable management and power requirements.

    ASI120MM Mini vs. ASI120MM-S: A Focus on Guiding

    The ASI120MM-S has a speed advantage for planetary work due to its USB 3.0 interface. The ASI120MM Mini, however, is purpose-built for guiding with a superior physical design.

    • Form Factor: The Mini's 36 mm diameter, 1.25" eyepiece-style body slides directly into any off-axis guider (OAG) or guide scope. The square body of the -S model can cause clearance issues with some focusers and filter wheels.
    • Weight: At only 0.2 lb, the Mini adds negligible weight to the imaging train, making it easier to balance your mount and putting less strain on the focuser.
    • Focus Position: The Mini is designed to reach focus at the same position as a typical 1.25" eyepiece, simplifying setup. Its 8.5mm native back focus and long body provide a greater focus travel range, making it easier to achieve simultaneous focus with your main imaging camera when used in an OAG.

    Integrated ST-4 Port and USB 2.0 Power

    The ASI120MM Mini simplifies your setup by drawing all power directly from the USB 2.0 port, eliminating the need for a separate DC power supply. The built-in ST-4 port allows for a direct, reliable connection to your equatorial mount's autoguider input. ZWO includes all necessary cables—a 2-meter USB cable for reaching your control computer, a shorter 0.5-meter cable for connecting to an ASIAIR, and an ST-4 cable—so you can start guiding right out of the box.

  • What is the main advantage of the ZWO ASI120MM Mini's monochrome sensor for guiding?

    A monochrome sensor is significantly more sensitive to light than a color sensor because it does not have a color filter array blocking photons. This allows the ASI120MM Mini to detect fainter stars with shorter exposures, resulting in more precise and reliable autoguiding.

    How does the ASI120MM Mini perform for imaging Jupiter with an 8" f/10 SCT?

    The ASI120MM Mini is an excellent match for this setup. An 8" SCT at f/10 has a focal length of around 2000mm, which frames Jupiter well on the camera's 1.2 MP sensor. The 3.75µm pixels are well-suited for planetary imaging. For optimal resolution, you would typically use a 2x Barlow lens to bring the final focal ratio closer to f/20, which better samples the detail resolved by the telescope.

    Can I use the ZWO ASI120MM Mini for deep-sky imaging?

    No, the ASI120MM Mini is an uncooled camera and is not recommended for long-exposure deep-sky astrophotography. The sensor's thermal noise would overwhelm faint details in exposures longer than a few seconds. It is designed specifically for high-frame-rate planetary/lunar imaging and autoguiding.

    Why does the ZWO ASI120MM Mini use USB 2.0 instead of USB 3.0?

    The ASI120MM Mini uses USB 2.0 as it provides more than enough bandwidth for its primary function as a guide camera, which uses short exposures (1-5 seconds). This choice allows for a more compact, lightweight, and power-efficient design focused on the guiding use case. While USB 3.0 offers higher speeds for planetary imaging, USB 2.0 is still capable of high frame rates using smaller regions of interest.

    What do I need to use the ASI120MM Mini with an Off-Axis Guider (OAG)?

    The camera's 1.25" nosepiece slides directly into the prism port of most OAGs. Its slim, 36mm diameter body prevents interference with the main imaging camera's light path. You simply slide the camera in or out of the OAG port to achieve focus on a guide star, then lock it in place.

    Can I attach a lens to the ZWO ASI120MM Mini for wide-field views?

    Yes. The camera includes an M28.5-CS adapter, which allows you to attach standard CS-mount lenses. This turns the ASI120MM Mini into a capable electronic finder or a wide-field camera for capturing meteor showers or constellation portraits.

  • Sensor 1/3" ON Semiconductor AR0130CS CMOS
    Resolution 1280 x 960 (1.2 MP)
    Pixel Size 3.75µm
    Sensor Diagonal 6mm
    Quantum Efficiency (Peak) 80%
    Full Well Capacity 13,000e-
    Read Noise 4.0e
    Dynamic Range 82
    ADC 12-bit
    Shutter Type Electronic Rolling Shutter
    Max Frame Rate (Full) 35 FPS
    Max Frame Rate (ROI) 118 FPS at 640x480, 224 FPS at 320x240
    Exposure Range 64µs - 1000s
    Camera Type Monochrome, Uncooled
    Back Focus 8.5mm
    Protective Window AR Coated
    Data Interface USB 2.0
    Guide Port ST-4
    Telescope Connection 1.25" Nosepiece
    Dimensions 36mm Diameter x 61mm Length
    Weight 0.2 lb
    Operating Temperature -5°C to 45°C
    OS Compatibility Mac, Windows, Linux

    • ASI120MM Mini Camera Body

      × 1

    • 1.25" Cover

      × 1

    • 2m USB 2.0 Cable

      × 1

    • 0.5m USB 2.0 Cable

      × 1

    • ST-4 Guide Cable

      × 1

    • 1.25" Extender

      × 1

    • M28.5-CS Adapter

      × 1

    • Quick Start Guide

      × 1

  • ZWO 2-Year Limited Warranty