OnStep is a full featured telescope controller firmware that was created and maintained by Howard Dutton.

As of late 2021, it runs on several types of boards with a variety of microcontrollers, including the Teensy, ST's STM32F103, STM32F303, STM32F446 and Esspressif's ESP32.

In order to convert a mount to OnStep, one needs to fill out a spreadsheet created by Howard that accounts for various parameters, such as one or two stages of gear reduction, microstepping, an motor shaft RPM.

Today, I released my OnStep Python API on Github. This API allows commands to be issued from any Python 3.x program to an OnStep controlled telescope.

This allows a lot of use cases, for example, testing certain scenarios, or automating certain tasks.

Several examples are provided as starting points on how to write your own programs.

Patches for features, and fixes are welcome.

This is a short video demonstrating how to use a Hall Effect sensor and a magnet to implement Periodic Error Correction (PEC).

Here is an example on eBay for a standalone 3144 Hall Effect Sensor. And here are the small neodymium magnets.

Over the winter, I worked with Howard Dutton, the author of OnStep Telescope Controller, to make it work with the low cost STM32 ARM Cortex M3 microcontrollers. This involved writing a hardware abstraction layer (HAL), so adding different architectures in the future would not be too hard, as it was.