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iOptron CEM120-EC "Advanced" GOTO Equatorial Mount w WiFi LAN (High res encoder on RA axis)

iOptron CEM120-EC "Advanced" GOTO Equatorial Mount w WiFi LAN (High res encoder on RA axis)
CEM120-EC Mount iOptron CEM120-EC Mount iOptron USB3.0 Ports USB Hub LAN
Incl. VAT 20.00 % ( £716.50 )
Product Code
Add CEM60 Accessories
Pier or Tripod options

The iOptron CEM120EC2 has ultra high resolution optical encoders on BOTH RA and DEC axes for the ultimate in tracking accuracy.

An extraordinary innovation in mount design. It has high precision encoders in both axes with real-time PEC giving tracking accuracy of up to 0.15 arc seconds RMS.
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 CEM120EC. It offers the benefits of our revolutionary “center balance” design: stability, accuracy, and smooth mechanical operation, while capable of carrying a payload up to 115 lbs (52 kg). 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 CEM120EC's performance is demonstrated by its low periodic tracking error of <0.15 arcsec RMS. Along with the stability aspect, the CEM120EC 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. 
CEM120EC Features:
  • 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 115 lbs (52 kg) with the mount weight of 57 lbs (26 kg)
  • Easy to use and reliable gear clutches
  • Adjustable counterweight shaft for 0º latitude operation
  • 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)<0.15 arcsec RMS
  • Real time periodic error correction (RPEC)
  • Built-in 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
  • CEM120EC mount head x1
  • Go2Nova 8407 V2 hand controller x1
  • 10 kg counterweight x2
  • Counterweight shaft x1
  • Hand controller cable x1
  • Serial cable (#8412) x1
CEM120-EC Technical specifications:


Center-balanced Equatorial Mount (CEM)


52kg (115 lbs), exclude counterweight*

Mount weight

26kg (57 lbs)

Payload/Mount weight ratio



All metal

Latitude adjustment range

0°~ 68° (0.5 arcmin division)

Azimuth adjustment range

± 5° (3 arcmin division)

Tracking accuracy (PE)

< 0.15 arcsec RMS

Worm period

240 sec


Real time PEC (RPEC)

Right Ascension worm wheel

Φ216mm, 360 teeth, zero backlash

Declination worm wheel

Φ216mm, 360 teeth, zero backlash



Right Ascension axle

Φ80mm, steel

Declination axle

Φ80mm, steel

Right Ascension bearings


Declination bearings


Counterweight shaft

Φ38.1x 540 mm (SS, anti-slip, 4.5kg)


10 kg (22 lbs)

Mount base size

210 x 230 mm

Motor drive

Precision stepper motor w/128 micro-step


0.07 arc seconds

Slew speed

4°/sec (960x) max.

Hand Controller

Go2Nova® 8407 V2, 8 line 21 character LCD

Power requirement

DC 12V, 5A

Power consumption


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/azi input

Level indicator


Dovetail saddle

Losmandy D, 17.2" (437mm)



Guiding port


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


Optional pier


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.


Lead-time: Approx. 5-14 Days depending on order cycle.

iOptron & Altair Astro reserve the right to change product design, specification and price without notice.

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