iOptron HEM27 Hybrid Harmonic Drive Equatorial GoTo Mount
iOptron HEM27 Hybrid Harmonic Drive Equatorial GoTo MountiOptron HEM27 Hybrid Harmonic Drive Equatorial GoTo MountiOptron HEM27 Hybrid Harmonic Drive Equatorial GoTo Mount
iOptron HEM27 Hybrid Harmonic Drive Equatorial GoTo MountiOptron HEM27 Hybrid Harmonic Drive Equatorial GoTo MountiOptron HEM27 Hybrid Harmonic Drive Equatorial GoTo Mount

iOptron HEM27 Hybrid Harmonic Drive Equatorial GoTo Mount

  (1 Review)
✓ 2 year warranty


Out of stock due 10-15 working days

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iOptron HEM27 Hybrid Harmonic Drive Equatorial GoTo Mount

£1759.00 £1583.00

About this product

Model:  iop_hem27
Part Number:  H272

New Hybrid Harmonic Drive Mount from iOptron

This portable, high-payload tiny titan will deliver an astronomy experience like never before. A mount head weighing in at 3.7kg / 8.15 lbs with a payload capability of 13.5kg / 29.74 lbs, without needing a cumbersome counterweight or shaft. 

Utilising state-of-the-art harmonic drive technology for the RA movement in tandem with backlash-free DEC worm/belt drive design, the HEM27s deliver unparalleled weight to payload efficiency.

Its black anodised all-metal CNC machined body is a sturdy, rugged platform that will perform at the highest level for many years.

Unique features such as an electronic friction break and power-down memory enable the mount safely stop and resume a GoTo slew or continue tracking even after an abrupt power loss (no need to realign and restart).

The HEM27EC features a high-precision RA axis encoder that delivers incredible tracking accuracy, enough that many will choose to image “sans” guiding. 


Please read the Quick Setup Guide (QSG) BEFORE setting up and operating the mount! Please also read the full online Instruction Manual. 
IOptron HEM mounts have a cable management system. To avoid cable damage, a mechanical stopper is implemented in RA to prevent the mount from rotating over 360 degrees.
The strain wave gear system provides high torque and strain, so damage to the stopper might happen if: 

1. ‘Site’ and ‘Time’ are incorrectly set
2. The mount starts from the incorrect Zero Position. Please perform 'MENU=>Zero Position=>Searching Zero Position’ to establish Zero Position
3. Manually slew the mount past meridian 20 degrees.

If you have any questions, please contact us or iOptron for support. 

iOptron's HEM27 FAQ page. 


  • Advanced harmonic drive technology
  • The payload capacity is 13.5 kg (29.7 lbs) with a mount weight of 3.7 kg (8.15 lbs)
  • CNC machined and cast metal body
  • Unique friction brake to safely stop movement during a planned or unplanned power interruption
  • 360-second gear period
  • Permanent periodic error correction (PPEC)
  • Go2Nova® hand controller with ~212,000 object database
  • Cable management system, no hanging exterior cables to moving parts
  • Dual saddle (Vixen and Losmandy-D styles)
  • Built-in zero position search and locator
  • Power down position and location memory
  • Integrated ST-4 auto-guiding port
  • Built-in Wi-Fi (via hand controller)
  • USB port for firmware upgrade and computer control
  • Soft carrying case
  • Two-year warranty

Go2Nova Hand Controller 8409

  • 212,000 object database & star identification
  • Large LCD screen with four lines and 21-character with backlit LED buttons
  • User-friendly interface
  • 9-speed setting for motor slew speed
  • Serial port for firmware upgrade and mount computer control

What's in the box

  • Telescope mount
  • Hand controller (HC) – Go2Nova® 8409 
  • Controller cable
  • AC adapter – 100‐240V 
  • Soft carry case


Mount Hybrid Equatorial Mount
RA Gear system StrainWave 17 (RA)/worm gear (DEC)
DEC Gear system Backlash-free worm/belt system
RA reduction ratio 120
Payload w/o CW * 29.14 lbs (13.5kg)
Mount weight 7.49lbs (3.4kg) w/o dovetail saddle, 8.15 ls (3.7kg) with dovetail saddle
Payload/Mount weight 3.65
Period 360 second
Drive motor Stepper motor
Structure Material All metal, CNC machined
Exterior finish Anodised black
PEC Yes, Permanent PEC
Latitude adjustment range 15º ~ 65º
Azimuth adjustment range ± 5º
Polar Scope No
Level indicator Level bubble
Control system GOTONOVA/Commander
Hand Controller Go2Nova® 8409 with ~212,000 objects database
Tracking Automatic
Maximum slew speed 6º/sec
Power consumption 0.5A(Tracking), 1A(GOTO)
Power Requirement 12V DC, 5A
AC adapter 100V ~ 240V (included, indoor use only)
Power off brake Electronic friction brake
Power-down memory Yes
Wi-Fi Built-in
Communication port Yes (Wi-Fi and USB)
Autoguide port Yes (ST-4 compatible)
Firmware upgrade Yes
Tripod Optional
Operation temperature -20ºC ~ 50ºC (hand controller -10ºC ~ 40ºC)
Warranty Two year limited

* 200mm, with payload center of gravity to the RA rotation axis. Or an OTA size of ~220mm.

Downloads / Manuals


Quick Start Guide
Instruction Manual

Firmware and Software:
Download Latest Firmware

iOptron Telescope ASCOM Driver:
Install ASCOM Driver and Commander

Customer reviews

Average Rating (1 Review):  
Write a Review and share your opinions!

Rating (max 5):  
HEM27 interim review
29 January 2024  | 

I'm going to start with a negative, that being the task of changing from vixen to losmandy saddle forms a task I decided will only happen once as I've now changed both set-ups to losmandy saddle plates. I played with the mount only to start with just to get things working with my asiair plus and my laptop running NINA. Then still indoors with scopes mounted (RASA 8 or 80mm f6 refractor setups). Balancing dec was easy enough, both setups didn't require counterweights and being tripod based I wanted to make sure I had no issues slewing without a CW especially with the RASA mounted. All checked out so next clear night (full moon!) it was first drive night for the mount. I used the asiair plus for PA which proved easy enough in both Az & Alt directions. Adjustments were made with both axles slightly tightened and left as is to avoid any changes that might change settings. I tried a mix of guiding exposures from 2 seconds down to half a second with a second giving me good guiding and lots of guide stars (9x 50 guide scope asi120mm camera).
I've given 4 stars because of the saddle and having to buy an additional losmandy plate to avoid fiddling with small wiring and screws to swap kit around otherwise it's really a solidly built mount, very very quiet and guides well.
If you only have a single setup then it's ideal, more than one then change to the same saddles.


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