Enrico Molinari

Electronic Control System for a German Equatorial Telescopic Mount: a Simple Hardware and Firmware Solution to Implement a Goto and Sidereal Tracking Function Enrico Molinari

Task of this book is to describe a conceptually simple and cheap solution to design an electronic board in order to implement an open-loop (so without feedbacks such as inertial sensors or rotary incremental encoders) control for a german equatorial telescopic mount, guaranteeing common goto and sidereal tracking functions to the system. Equatorial mount used is a Fast Linear Reverse by Avalon Instruments, which mounts a stepper motor in celestial right ascension axis and a stepper motor in celestial declination one. We will talk about stepper motors (by Sanyo Denki), relative bipolar chip-drivers (L6208 by STMicroelectronics)and their embedded power circuitries (with a particular focus on working of full H-bridges), about digital/analogical converters (AD7305 by Analog Devices) and firmware required to implement a proper microstepping drive by exploiting a simple 8-bit microcontroller by STMicroelectronics. Electronic board discussed here is a product designed and sold by LTEC srl and it has been matter of work for the author of this book during his internship at LTEC.