Astronomy Specialist


$10,700.00 $12,999.00

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Grab yourself a bargain on this ex-demo CEM120 EC2! The mount is in as-new condition and comes with the original accessories.

Recognizing the growing demand for an accurate and stable equatorial mount with the versatility to carry larger instruments and more complex imaging arrays, iOptron created the CEM120EC2.

It offers the benefits of iOptron's revolutionary “center balance” design: stability, accuracy, and smooth mechanical operation, while capable of carrying a payload up to 52 kg (115 lbs). The “center balance” design’s natural stability is due to its focusing the mount along with payloads weight directly over the center of the pier or tripod. The gears are spring-loaded for reduced backlash.

The CEM120EC2 utilizes two high resolution encoders, one on each axis. The two encoders enable the mount to perform dual axes tracking. With advanced sky modeling the CEM120EC2 will be able to account and adjust for polar alignment error as well as changes in atmospheric (refractive) distortion. Fixed home sensors on each axis, allow the mount to save alignment models after power off too to be used on future nights.

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.

Note: The iOptron CEM120 does not come with a tripod. It can be attached to either the iOptron Tri-Pier 360, the regular Tri-Pier with its optional adapter plate, or the Geoptik Hercules tripods with the optional adapter plate




  • A new design, center-balanced equatorial mount (CEM) for maximum payload with natural stability
  • Observatory astrophotography mount ideal for both visual and Astro-photographers
  • Payload of 52 kg (115 lbs) with the mount weight of 26 kg (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)<±3.5 arcsec
  • 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


Center-balanced Equatorial Mount (CEM)
Max payload 52 kg (115 lbs) excluding counterweight
Mount weight
26 kg (57 lbs)
Payload/Mount weight ratio 2
Body material
All metal, CNC machined, anodized
Periodic error (PE) <±3.5 arc seconds
PEC Yes, Permanent PEC
Worm period 240 sec
Right Ascension worm wheel Φ 216 mm, 360 teeth, zero backlash
Declination worm wheel Φ 216 mm, 360 teeth, zero backlash
Right Ascension axis shaft Φ 80 mm steel
Declination axis shaft Φ 80 mm steel
Right Ascension bearing Φ 125 mm
Declination bearing Φ 125 mm
Worm diameter Φ 26 mm
Motor drive Precision stepper motor, 128 x microdivision
Resolution 0.07 arc seconds
Latitude adjustment range 0º ~ 68º (0.5 arc minute division)
Azimuth adjustment range ± 5º (3 arc minute division)
Polar Scope Optional iPolar electronic polar scope
Level indicator Level bubble
Hand Controller Go2Nova 8407 V2, 8 line 21 character LCD
Meridian treatment Stop (0-14° pass), flip
Max slew speed 4°/sec (960 x)
Power consumption 0.7A (tracking), 1.8A (GOTO)
Power requirement 12V DC, 5A, 5.5mm x 2.5mm plug
Park position Horizontal, vertical, current, Alt-Az input
Communication port RS232, USB, LAN, WiFi
Autoguide port ST-4
Cable management 2 x DC 12V (1A), DC 5V(1A), 2 x DC (5A), ST4, 6P6C, 4 x USB2.0, USB3.0 (powered), USB for PS, AUX
Counterweight shaft Φ 38.1 x 540 mm, Stainless Steel, anti-slip 4.5 kg
Counterweight 2 x 10 kg (22 lbs)
Tripod Optional pier
Dovetail saddle Losmandy D, 17.2" (437mm)
Mount base size 210 x 230 mm
Warranty Two year limited
SKU IO-7302
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