iOptron CEM120 Equatorial Mount

iOptron CEM120 Equatorial Mount

Due to high demand and global product shortages due to the pandemic, please call for availability.

The All NEW iOptron CEM120!

An extraordinary innovation in mount design...Now with a new payload!

Recognizing the growing demand for an accurate and stable equatorial mount with the versatility to carry larger instruments and more complex imaging arrays, we created the iOptron CEM120. It offers the benefits of our revolutionary “center balance” design: stability, accuracy, and smooth mechanical operation, while capable of carrying a payload up to 52kg (115 lbs). The “center balance” design’s natural stability is due to its positioning of the mount and payload weight directly over the center of the pier or tripod.

The CEM120's performance is demonstrated by its low periodic tracking error of ±3.5 arc seconds. Along with the stability aspect, the CEM120 features an advanced cable management system consisting of more ports in more locations preventing tangle ups and reducing the chance of fractured cables. It also adds some new features to the CEM family like Wi-Fi and LAN for remote operation and easy to use, reliable clutches on both axes.

Optional heavy duty Tri-Pier 360 and Permanent Pier are available for order.

Optional Tri-Pier adapter for light weight payload ( 8036-120) is also available for $129 USD. It can be modified for permanent pier mounting.


  • A new design, center-balanced equatorial mount (CEM) for maximum payload with natural stability
  • Observatory astrophotography mount ideal for both visual and astro-imaging applications
  • Payload of 52kg (115 lbs) with the mount weight of 26kg (57 lbs)
  • Easy to use and reliable gear clutches
  • Precision altitude and azimuth adjustment
  • Precision stepper motor with 0.07 arcsec accuracy for precise GOTO and accurate tracking
  • Polar alignment routine for those who can't see the Pole Star
  • Go2Nova® 8407 V2 controller with Advanced GOTONOVA® GOTO Technology with built in heater
  • High precision tracking with low periodic error (PE)
  • Permanent periodic error correction (PPEC)
  • 32-channel Global Positioning System (GPS)
  • Built-in WiFi and LAN for remote operation
  • Integrated ST-4 autoguiding port
  • Advanced cable management system with more choices
  • Spring loaded, individual adjustable Losmandy saddle

Included Items

  • CEM120 mount head x1
  • Go2Nova 8407 V2 hand controller x1
  • 10 kg counterweight x1 (free extra one for limited time)
  • Counterweight shaft x1
  • Hand controller cable x1
  • Serial cable (#8412) x1


  • Mount: Center-balanced Equatorial Mount (CEM)
  • Payload: 52kg (115 lbs), exclude counterweight*
  • Mount weight: 26kg (57 lbs)
  • Payload/Mount weight ratio: 2
  • Material: All metal
  • Latitude adjustment range: 0°~ 68° (0.5 arcmin division)**
  • Azimuth adjustment range: ± 5° (3 arcmin division)
  • PE (by encoder): < ±3.5 arcsec
  • Worm period: 240 sec
  • Right Ascension worm wheel: 216mm diam., 360 teeth, zero backlash
  • Declination worm wheel: 216mm diam., 360 teeth, zero backlash
  • Worm: 26mm diam.
  • Right Ascension axle: 80mm diam., steel
  • Declination axle: 80mm diam., steel
  • Right Ascension bearings: 125mm diam.
  • Declination bearings: 125mm diam.
  • Counterweight shaft: 38.1 diam.x 540 mm (SS, anti-slip, 4.5kg)
  • Counterweight: 10 kg (22 lbs)
  • Mount base size: 210 x 230 mm
  • Motor drive: Precision stepper motor w/128 micro-step
  • Resolution: 0.07 arcseconds
  • Slew speed: 4°/sec (960x) max
  • Hand Controller: Go2Nova® 8407 V2, 8 line 21 character LCD
  • Power requirement: DC 12V, 5A
  • Power consumption: 0.7A(Tracking),1.8A(GOTO)
  • Polar Scope: Optional electronic polar scope
  • Meridian treatment: Stop (0-14° pass), auto flip
  • Zero position: Automatic zero search
  • Park position: Horizontal, vertical, current, alt/az input
  • Level indicator: YES
  • Dovetail saddle: Losmandy D, 437mm (17.2")
  • GPS: YES
  • Guiding port: ST-4
  • Communication port: RS232, USB, LAN, WiFi
  • Cable management : 2xDC12V (1A), DC5V(1A), 2xDC (5A), ST4, 6P6C, 4xUSB2.0, USB3.0 (powered), USB for PS, AUX
  • Pier/Tripod: Optional pier
  • Warranty: Two year limited

* These are only guidelines. Some telescopes are very long or very big for their weight and may require a larger mount. Remember also that imaging requirements are more rigid than visual observation.

** If your latitude is <10°, please contact iOptron for special CW mounting housing.