iOptron GEM28 German Equatorial GoTo Mount
iOptron GEM28 German Equatorial GoTo MountiOptron GEM28 German Equatorial GoTo MountiOptron GEM28 German Equatorial GoTo Mount
iOptron GEM28 German Equatorial GoTo MountiOptron GEM28 German Equatorial GoTo Mount

iOptron GEM28 German Equatorial GoTo Mount

  (6 Reviews)
✓ 2 year warranty


1x in stock shipped 1-2 working days

About this product

Model:  iop_gem28_tp_hc
Part Number:  G282A1

This compact German Equatorial Mount weighs only 4.5 kg (10 lb) yet supports a payload of up to 12.7 kg (28 lb)!

IOptron achieved this high weight-to-payload ratio using design and manufacturing methods to reduce mass from their similarly specified CEM mounts. So if you have admired the iOptron CEM series but prefer the more traditional GEM design, or need a mount that works at higher (over 60º) latitudes, then the iOptron GEM28 is for you. 

Features include precise whisper-quiet stepper motors (periodic error < ± 10 arc seconds), large, easy-to-use, quick-lock gear clutches, integral WiFi for easy connectivity and recordable Permanent Period Error Correction (PPEC). 

It can be purchased with iOptron AccuAlign optical polarscope or iPolar electronic polar finder. 

The GEM28 also has iOptron's latest advanced Go2Nova® 8409 Hand controller with a large 4-line LCD screen and a 212,000 object database. 


  • Compact German Equatorial Mount
  • Payload of 28 lbs (12.7 kg) with a mount-only weight of 10 lbs (4.5 kg)
  • Precise stepper motors with low power consumption
  • Low periodic error (< ± 10 arc seconds)
  • Permanent Period Error Correction (PPEC)
  • Ideal for entry-level and intermediate astrophotography
  • Large easy to use quick-lock gear clutches on R.A. and DEC axes
  • Operational range from 10° to 70°
  • Choose iOptron AccuAlign optical polarscope or iPolar electronic polar finder
  • Go2Nova® 8409 with 212,000 object database & star identification
  • Integrated WiFi for full function control via SmartPhone/Tablet/Computer
  • ST-4 auto-guiding port
  • USB port
  • Optional 32-channel Global Positioning System (GPS)
  • Serial port for firmware upgrade and computer control
  • Spring-loaded Vixen-style saddle
  • Available with a 1.5-inch stainless steel tripod or a 1.75" LiteRoc tripod
  • Die-cast metal tripod spreader with accessory tray

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

Hard Case

Includes a hard with custom-fit foam padding to hold the mount in place and cushion it from impacts. The exterior has reinforced edges on the outside to help minimise denting and damage. There are dual trigger latches to secure the lid in place and a carry handle.



What's in the box

  • Telescope mount with Optical Polarscope or iPolar
  • Hand controller (HC) – Go2Nova® 8409 
  • Tripod with accessory tray – 1.5‐inch or 1.75 inch LiteRoc 
  • Counterweight – 10.4 lbs X1 (4.7 kg) 
  • Counterweight shaft 
  • Controller cables x2 
  • RS232‐RJ9 serial cable 
  • AC adapter – 100‐240V 


Mount German Equatorial Mount
Payload * 28 lbs (12.7kg), exclude counterweight
Mount weight 10 lbs (4.5kg)
Payload/Mount weight 2.80
Structure Material All metal, Casting + CNC machined
Exterior Finish Powder coating
Periodic error (PE) ** <±10 arcsec
PEC Yes, Permanent PEC
Worm period 600 sec
Right Ascension worm wheel Φ88mm, 144 teeth aluminum
Declination worm wheel Φ88mm, 144 teeth aluminum
Right Ascension axis shaft Φ35mm steel
Declination axis shaft Φ35mm steel
Right Ascension bearing Φ55mm ball bearing
Declination bearing Φ55mm ball bearing
Worm gears Φ15.2mm, Brass
Motor drive 1.8º stepper motor, 128X microdivision
Resolution 0.17 arc seconds
Transmission Synchronous belt
Latitude adjustment range 10º ~ 70º
Azimuth adjustment range ± 6º
Polar Scope iPolar TM electronic polar scope
Level indicator Level bubble
Hand Controller Go2Nova® 8409 with ~212,000 objects database
Tracking Automatic
Slew speed 1×,2×,8×,16×,64×,128×,256×,512×,MAX(6º/sec)
Power consumption 0.6A (Tracking), 0.9A (GOTO)
Power requiremention 12V DC, 5A
AC adapter 100V ~ 240V (included)
Power-down memory Yes
Wi-Fi Built-in
Communication port Yes (Wi-Fi and USB)
Autoguide port Yes (ST-4 compatible)
Firmware upgrade Yes
PC computer control Yes (ASCOM)
Counterweight shaft Φ20x306mm (M16), Stainless Steel
Shaft extension Φ20x120mm (M16), Stainless Steel
Counterweight 10 lbs (4.5kg)
Tripod 1.5" Stainless Steel (5kg)
Dovetail saddle 3.8" Vixen-style, center adjustable
GPS Optional external 32-channel GPS
Autoguiding Optional external iGuider 1
Operation temperature -10ºC ~ 40ºC
Warranty Two year limited

Downloads / Manuals




Download Latest Firmware 

iOptron Telescope ASCOM Driver:

Install ASCOM Driver and Commander 

Customer reviews

Average Rating (6 Reviews):  
Write a Review and share your opinions!

Rating (max 5):  
Excellent mount with some issues
12 June 2022  | 

I've been imaging with this mount for six months now and I'm very happy with it overall.
But... Like many others I had to fix the mesh tension.
Sometimes it will halt when pointing at zenith for a few minutes and has to be reset. So I made a habit to reset the mount after taking flats jic.
I can keep the mount standing for days with minor corrections to PA every other day.
With a Celestron C6 with Hyperstar c6v4 I get guiding averages of 0.7-0.8 rms.
With the C6 and f6.3 reducer it's more into the 0.9-1 so I probably need a bigger guide scope for that setup.
All in all it's a great mount in my experience.

Rating (max 5):  
Great Mount, flakey software & dodgy firmware
16 May 2022  | 

I had been pondering over what mount to get for sometime and settled for the GEM28 as it offered a good balance between portability and payload capacity.

The mount itself is fantastic and if you plan to use the mount out the box with the hand controller you wonít go far wrong. It has buttery smooth gearing and makes less noise that a Grass hopper breaking wind.
However, the issues with software, firmware and ioptronís lack of supporting documentation make this an interesting mount to get automated.

In a nutshell I couldnít get this mount to run consistently with indi servers (astroberry etc) it would run first time and then after this not connect. From my limited knowledge it appears to be due to a serial / USB error, first connect the handset and USB talk happily, next connect the handset gives up leaving the USB looking for a connect and failing. The only way to get them to talk again would be to reflash the handset. Not ideal and after 2 whole days of playing with work arounds I conceded.

With a lot of toing and froing I ended up settling for a Windows solution, NINA. IOptrons commander software is horrible and it appears most anti viruses donít like it either. So when installing be sure to stick it on the exemptions list before calling It names. Given I now only have to interact with it briefly while NINA loads up control with it

Its been an emotional weekend.

Rating (max 5):  
16 December 2021  | 

Only reason l gave 4 stars, problem with firmware download and still cannot download, otherwise it's a nice bit of kit. Unfortunately lve not been able to use due to the weather. As always FLO AS helpful as ever thy tried to help me with the firmware problem , running with ascom and hand control seems to be working OK.

Rating (max 5):  
Ioptron gem28 review
03 December 2021  | 

I wanted to upgrade to a better mount for imaging yet wanted it to be portable making it much easier to move and handle yet firm enough to handle my rig (around 6kg).

It got to either the HEQ5 or the gem28. The ioptron is abit pricier and can holds less but much ligher and seemed better for imaging with the spring worm gear.

So i went for the gem28 literock tripod no ipolar as i use sharpcap to get an excellent alignment so it felt unneeded.

Got it few days ago. Shipping and handling - perfect as always. FLO is pretty much the BEST online shopping store when it comes to price, shipping time and support.
The case is very usefull allowing to transport it and if you just leave the mount assembled (watch out that it wont get bumped) it can be used as an accessory suitcase.

I chose the 1.75 tripod. Its compact yet very durable. I think its a must but havent tried the 1.5 so...

I dont need the ipolar as mentioned. The accualign - polar scope of the gem28 is pretty high quality, comes with lighting option.
Only use that as a first guideline.

I assembled the mount and tripod. Abit different than the skywatcher ones. Firsy tip: It is very recommended to read the manual before doing anything. And here comes the first thing to consider, the mount has spring loaded worm gears. Basically it enables a much more precise tracking yet when engaged, bumping the mount can damage the spring so it needs to be taken with care. Thats pretty much the only downside i found for that mount and since its done for a precise tracking its an advantage for me.

First light was yesterday. Very good tracking. Acually crazy good conpared to my old eq5 pro. Phd measured 5 arc min error.. amazing. Guiding was very easy to setup. Bearings and axes are butter smooth. A premium quality mount... i am very happy. Very recommended

Rating (max 5):  
iOptron GEM28 Go-To mount
01 November 2021  | 

I purchased this mount a week ago as a set along with the iPolar, carry case and 1/75Ē tripod when it became available at FLO and was very pleased with the quality of manufacture and indeed that anti-vibration pads came fitted on the tripod legs as standard, a nice touch.

The mount is lightweight and thus very portable and I am able to lift the whole assembly together with my wide field imaging equipment as one item saving on set up time and disassembly between uses each night.

I will be mostly using the hand controller for operating the mount and some form of holster accessory to place the hand controller on one of the tripod legs during sessions would be useful. I have also employed thick elastic and Velcro fastening to secure the mains power unit to one of the tripod legs rather than balance it on the eyepiece tray. A 3-D printed accessory would be useful here.

As a full package from iOptron wi-fi control requires more development and publicity by iOptron. I was forced into exploration across the Internet and left to connect the dots. Nonetheless I have been able, by piecing together scattered online information, to control the mountís slewing by both usb cable and wi-fi with iOptronís Commander software + Stellarium. More advice on what other planetarium software will/wonít work with the inbuilt iStarFi equivalent wi-fi unit would be welcomed.

I can recommend the package to other astronomers looking for a quality lightweight imaging solution. I am also looking forward to using the mount under clear skies whenever they emerge!

Rating (max 5):  
Robust Build Quality
21 April 2021  | 

My first few days with the mount. Works well with AsiAir Pro. Build quality is extra-ordinary given the price-point and ultra-portability of the mount. I cannot thanks enough FLO for the assistance they provided while getting the mount. I was waiting for CEM26, but GEM28 proves to be better in balance (and 2lbs more payload!!)
Great Job FLO.


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