OnStep retrofit kit for Losmandy G11, GM8, G9, AZ8, HGM200 and their Celestron equivalent non GoTo mounts. Onstep is the most popular alternative to the expensive Gemini 2 retrofit kit goto system.

This kit is the same for the above mentioned mounts, only main firmware differenciate, wich one you can easilly change with the firmwares supplied on this site.

Based on Nema 17 stepper motor positioning system, this kit includes all necesary to fully control your mount, hand controller is optional but not needed, package content:

  • 2x Nema17 0,9º Step Angle Stepper Motors (5,4VDC, 0,9A, 36Ncm nominal Specs), installed on brackets.
  • 2x Motor-to worm gear couplers.
  • 2x Flat RJ45 cables 1 metter long.
  • Main Drive with TMC2130 stepper motor drivers installed, 2x antenna for BT and WiFi.
  • 2x reusable nylon fasteners, 4x inox screws for the motor brackets.


  • Permanent PEC
  • Up to 6 star goto asisted polar aligment correction.
  • Automatic refraction rate compensation.
  • Custom park and home positions.
  • Integrated Bluetooth and WiFi server/command channel.
  • Refraction rate compensation
  • Automatic meridian flip, meridian flip pause at home.
  • Custom backslash setting.
  • Up to 600x slew rate.
  • Custom limits (overhead, horizon, meridian)
  • Custom observing sites.
  • Large object database: Solar System, Messier, NGC/IC, Herschel, Bright Stars, User Custom Catalog.
  • Manual speed/guide speed rates: 0,5x, 1x, 2x, 8x, 24x, 48x, 300x
  • Slew Rate: Adjustable 150 to 600x
  • Tracking: Sidereal, Lunar, Solar, Fine Adjust
  • Power source: 2A 12VDC (up to 400x) for 600x slew rate use 18VDC (recomended). Max 24VDC. 
  • Tracking resolution, in arc-sec:  G11: 0,035  GM8/G9/AZ8: 0,07  HGM200: 0,046
  • Guide resolution, in arc-sec: G11: 0,56  GM8/G9/AZ8: 0,56  HGM200: 0,37


Installation is as easy as this example for G11, other Losmandy mounts are similar, they share the same motor hardware design;


Compiled firmwares, source code and manual to be updated soon.

Defaul Device name for BT and WiFi are "OnStep"

Default WiFi key is "password", default IP is: (port 9999 for command channel and android app), for web browser conection just type: in your web  browser address tab. Wifi SSID and key can be changed, BT device can not. In case of wifi key lost you can restore defaults by uploading again wifi firmware part.

You can select your Losmandy drive to be shipped with the right firmware installed from the available options, motors are the same for G11, GM8, G9, AZ8 & HGM200.

Write a review

Note: HTML is not translated!
    Bad           Good

Losmandy OnStep G11-GM8- G9-AZ8-HGM200 GoTo Kit - Gemini2 Retro-Fit Kit Alternative

  • Brands Instein Astro
  • Product Code: Losmandy G11 GoTo Kit
  • Availability: In Stock
  • 360.00€

Available Options