iOptron CEM40 Center Balanced Equatorial GoTo Mount
iOptron CEM40 Center Balanced Equatorial GoTo MountiOptron CEM40 Center Balanced Equatorial GoTo MountiOptron CEM40 Center Balanced Equatorial GoTo Mount
iOptron CEM40 Center Balanced Equatorial GoTo MountiOptron CEM40 Center Balanced Equatorial GoTo MountiOptron CEM40 Center Balanced Equatorial GoTo Mount

iOptron CEM40 Center Balanced Equatorial GoTo Mount

  (3 Reviews)
✓ 2 year warranty


2x in stock shipped 1-2 working days

About this product

Model:  iop_cem40_7400a-hc_1.5
Part Number:  C402A1

Next generation design! 

The iOptron® CEM40 mount is a remarkably capable center-balanced equatorial mounts 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 patent-pending Universal Self-Centering Saddle 'USCS' accommodates Losmandy and Vixen-style dovetail plates. It 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 (8027) 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 (< ± 7 arc seconds)
  • Permanent periodic error correction (PPEC)
  • 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 8” Losmandy/Vixen saddle
  • Optional 1.5 or 1.75" inch heavy-duty stainless steel tripod (5kg / 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

Supplied in two boxes. 

  • CEM40 mount head
  • CW shaft
  • GO2Nova 8407+ hand controller with cord. 
  • 1x 11lb (5kg) Counterweight (if ordered with a tripod)
  • 1.5" or 1.75" steel tripod if applicable


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)** <±7 arcsec
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     Φ28X410 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 8" Losmandy D & Vixen
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" or 1.75" Stainless Steel tripod or tri-pier
Hard Case Optional
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 CEM40 Instruction Manual


Coming soon

iOptron Telescope ASCOM Driver:

Coming soon

Customer reviews

Average Rating (3 Reviews):  
Write a Review and share your opinions!

Rating (max 5):  
Overall and excellent mount
Monday, 9 August 2021  | 

The mechanics and build are excellent - it is a beautiful piece of machinery. Updating the firmware is a real pain in the a*se, even when you know itís a possible issue in advance, and updating the hand controller firmware requires you to buy a RJ9 to RS232 lead plus a RS232 to USB converter if you bought your PC anytime after the 1900s. Neither are included and there is no *modern* alternative. Theyíre not expensive - itís just annoying that after spending the best part of £2k on a mount, there is no way to update the firmware with the leads provided. The included instructions were for the wrong mount too, but theyíre all online of course. IOptron email support are distinctly failing to help on this either - though of course FLO have helped as much as they could.
Once you surmount these teething issues, itís a great mount and I would recommend it - especially if you need portability with 18kg visual or ~10kg imaging payload capacity.

Rating (max 5):  
Changes to CEM40 mount
Saturday, 1 May 2021  | 

We have had a recent disappointing experience with a CEM40 we ordered. In the end we sent the mount back and asked for a refund which we received no problem from FLO. We just want to make anyone contemplating buying this mount aware of a few things. It is likely that the mounts port configurations might change so please consult the iOptron website to be fully aware of any changes, also ask the guys at FLO to be sure that any current changes to the mountís connectivity suits your requirements. We didnít test out the mount so we assume its functionality with the handset is OK but we did have problems with a loose USB connection which is now the only one to the mount that handles all of the usb inputs and is the connection to the iPolar. Anyone also buying the case at the same time should note that iOptron will transport the mount in the case and so the it will not necessarily arrive in pristine order. We have given the mount one star to get people to look at this review it isnít a reflection on how good it performs as we didnít get to test that.

Rating (max 5):  
CEM 40
Tuesday, 30 July 2019  | 

Received this mount last week, FLO were excellent service. I been out a few times under limited clear skies. The Ipolar works a treat, my first attempt getting 3.5 arc minutes within the NCP.
The tracking seems very good as is the goto's . Also only had a limited time guiding using ST4, but PHD2 was giving excellent results.
The 2 inch tripod is very nice and extremely stable.
all in all im a very happy man


Please fill in the form below to ask a question.


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

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