Alcor - A Microcontroller-Based Control Circuit for Conventional AC Telescope Drives
Many telescopes still use 50- or 60-Hz AC motors controlled by variable-frequency AC power sources. This paper describes a programmed microcontroller that can be used as the oscillating element in such drive controllers, providing efficient two-phase drive, smooth frequency changes, and precise sidereal and lunar rates.
IMPORTANT NOTE: The PIC16F84 and PIC16F84A are not interchangeable. The assembly-language program must be assembled for the right one. Be sure you download the version that corresponds to the processor you are using. The PIC16LF84A is a complete substitute for the PIC16F84A and is what I am now using for new Alcor circuits. It uses the same .ASM and .HEX files.
- Paper in PDF as published in Journal of the B.A.A.
- Original manuscript (same paper) in PDF
- Free PDF reader (Adobe Acrobat Reader)
- PIC16F84 code (in assembly language)
- PIC16F84 code (in .hex format)
- PIC16F84A code (in assembly language)
- PIC16F84A code (in .hex format)
- Fast-slewing version of Alcor (60 Hz only) for '84A (in assembly language)
- Fast-slewing version of Alcor (60 Hz only) for '84A (in .hex format)
- LX3 version for PIC16F84 (in assembly language)
- LX3 version for PIC16F84 (in .hex format)
- Alcor circuit with dec. motor relays, as built for the Atlanta Astronomy Club
- Schematic circuit diagram of Meade LX3 telescope base
- Plans for a simple PIC16F84 programmer
- Programmed chips are available worldwide from Dontronics in Australia.