iOptron CEM40-EC Center Balanced Equatorial GoTo Mount with RA Encoder
iOptron CEM40-EC Center Balanced Equatorial GoTo Mount with RA EncoderiOptron CEM40-EC Center Balanced Equatorial GoTo Mount with RA EncoderiOptron CEM40-EC Center Balanced Equatorial GoTo Mount with RA Encoder

iOptron CEM40-EC Center Balanced Equatorial GoTo Mount with RA Encoder

£2,695.00✓ 2 year warranty


Out of stock due 30-40 working days

About this product

Model:  iop_cem40ec_7420eca
Part Number:  C404A

Features include an integrated Right Ascension encoder! 

The iOptron® CEM40EC is a remarkably capable center-balanced equatorial mount and the first to feature iOptron's next generation design.

Weighing in at only 15.8lbs, it can support a payload of up to 40lbs. Which is remarkable! 

Features include iOptron's integrated electronic polar finder scope, known as the iPolar, which ensures accurate polar alignment even when the pole star is obscured. 

Large Clutch levers on the quick-lock drive engagement system make it easy to lock the gears into place. 

Innovative iOptron Technology

IOptron's 8” saddle accommodates both Losmandy and Vixen-style dovetail plates (also accepts Sky-Watcher & Celestron dovetails). 

In addition the CEM40 features iOptron's ultra-quiet, low-power consumption stepper motor drive system for precise pointing and tracking. 

Computerised Mount Features

Using iOptron's Go2Nova® 8407 GOTO hand controller you can automatically point and centre any of the celestial targets (depending of course on date and location) contained in it's 359,000+ object database! 

With the included tripod, 5 kg counterweight and computerised GOTO technology, observers are just a telescope away from an impressive viewing experience!


  • New design, centre-balanced equatorial mount (CEM) for maximum payload and minimum mount weight
  • Designed for both visual astronomy and astrophotography
  • Maximum payload of 40 lbs (18 kg) with the mount weight of only 15.8 lbs (7.2 kg)
  • All metal and CNC machined with red/black anodising
  • Easy to use quick-lock gear clutches
  • Integrated iPolar electronic polar finder
  • Low periodic error ( PE< 0.25 arc seconds RMS)
  • Real-time periodic error correction with high resolution encoder (RPEC)
  • Precision stepper motor for precise GOTO and accurate tracking
  • Go2Nova® 8407+ controller with Advanced GOTONOVA® GOTO Technology with built-in heater
  • Integrated ST-4 autoguiding port
  • 32-channel Global Positioning System (GPS)
  • USB communication port
  • Cable management system
  • New, patent-pending iOptron universal saddle
  • Includes hard case
  • Optional 1.5 inch heavy-duty stainless steel tripod (5kg) or 2 inch heavy-duty stainless steel tripod (8kg)
  • Optional WiFi for mount control via SmartPhone/Tablet/Computer

Go2Nova Hand Controller 8407

  • 200,000+ object database
  • 8 line, 21 character back lit large screen LCD
  • Low temperature operation as low as -20ºC
  • User friendly interface
  • 9 speed slew control with quiet mode
  • Large object database
  • Serial port for firmware upgrade

What's in the box

Mount head only:

  • CEM40-EC mount head
  • CW shaft
  • GO2Nova 8407+ hand controller with cord.

Version with Tripod:

  • CEM40-EC mount head
  • CW shaft
  • 1x 5kg (11lb) Counterweight
  • GO2Nova 8407+ hand controller with cord. 
  • 1.5" OR 1.75"; steel tripod


Mount Center-balanced Equatorial Mount (CEM)
Max Payload 40 lb (18 kg), exclude counterweight*
Mount weight 15.8 lb (7.2 kg)
Payload/Mount weight ratio 2.5
Structure Material     All metal, CNC machined, red/black anodised
Latitude adjustment range 0º ~ 60º(special CW shaft mounting if <10° )
Azimuth adjustment range ± 6º
Tracking accuracy (PE)**

<0.25 arcsec rms

PEC Real-time PEC (RPEC)
Period 400 sec
Worm diameter     Φ17mm, Brass
Right Ascension worm wheel     Φ110mm, 216 teeth, zero backlash
Declination worm wheel Φ110mm, 216 teeth, zero backlash
Right Ascension axis shaft Φ45mm steel
Declination axis shaft     Φ45mm steel
Right Ascension bearings Φ68mm
Declination bearings Φ68mm
Counterweight shaft     Φ28x280 mm, Stainless Steel (1.2 kg)
Counterweight 1x 5kg (11lbs) 
Motor Precision stepper motor, 1.8º/128X micro-step
Motor resolution 0.08 arcsec (200 PPS)
Transmission Synchronous belt
Hand Controller     Go2Nova® 8407+, 8 line 21 character LCD
Star Database 359,000+, star identification
Power DC 12V, 5A
AC adapter 100V ~ 240V (included)
Power consumption 0.6A (Tracking), 0.9A (GOTO)
Power-down memory Yes
Polar scope Internal iPolar electronic polar scope
Meridian treatment Stop (0-10° pass), flip
Operation temperature -20°C ~ +45°C
Zero position Automatic zero search
Dovetail saddle iOptron Universal Saddle, 8"
Max slew speed 4.5°/sec (1080x)
Guiding port ST-4
Communication port USB
WiFi External (optional)
Cable Management DC12V (3A), ST4,USB
Tripod Optional 1.5" Stainless Steel(5kg), 2" Stainless Steel (8kg) or tri-pier
Hard Case Inlcluded
Operation Temperature -10ºC ~ 40ºC
Warranty Two year limited

* This is only guideline. Some telescopes are unusually long or large for their weight so may require a larger mount. Consider also max' payloads for astrophotography are typically 1/3 less than for visual astronomy. 
** Measured with encoder, 400 seconds

Downloads / Manuals


iOptron CEM40EC Instruction Manual


Coming soon

iOptron Telescope ASCOM Driver:

Coming soon

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Q1. Does the CEM40 mount fit the iOptron tri-pier?

Yes - the CEM40 fits directly to the tri-pier, no additional adapters are required.

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