Here, I think you will find a small and fine Autoguiding Interface for the (Synta) Skywatcher HEQ-5 and EQ-6. The interface uses the LX200 protocol and is therefore usable with nearly every piece of astronomical software that can control your telescope (I do not know of any program that does not support the LX200 protocol). No modification of your mount is required, because the interface connects between your mount and its hand controller. The connection with a PC is by a serial connection cable (not a null modem or data transfer cable). The following LX200 commands are supported: #:Me#, #:Mw#, #:Mn#, #:Ms#, #:Q#, #:Qe#, #:Qw#, #:Qn#, #:Qs#, #:RG#, #:RM#, #:RS#. Version 2 supports connections with professional guiders like those from SBIG and Pictor so you can use the interface without the PC. If you wish, you can purchase the autoguider as a kit, and build it yourself. The autoguider is offered in 3 versions:
The Autoguider get's replaced by the EQ-6 MCU Update Kit!
If you want to construct your interface yourself, I am providing the instructions below free of charge.
The interface consists of a second box without buttons and switches. It works like the original using an a Atmel AT89C2051 (V2 = AT89C4051) microprocessor. The button and switches functions are implemented through the Autoguiding software. The construction is very simple, because there are only 2 IC's (the microprocessor and the serial level shifter MAX232).
The wiring is also not difficult. You only must watch, that the wires from the cable are attached correctly.
Because the colors of the serial cable wires can be different for different cables, I do not refer to wire color, instead I used the description of the handbox (open the handbox and have a look at the plate).
Connetion of the D-Sub Connector:
2 - TxD (RS232)
3 - RxD (RS232)
5 - GND
7 and 8 connected.
1 - DEC+
4 - DEC-
6 - RA+
9 - RA-
Thats it, happy Autoguiding :-)
Here a small Tool you can use to test you fabrication (Virtual Handbox) ;-)
Lastly, so there are no misunderstandings. The figures and images above are freely reproducible for private use only. Commercial implementation of these circuits are permitted only by express written permission.: Reproduction and use of these circuits are at your own peril. The author is not responsible for any damage to you or your possessions that you might incur. It may sound terrible, but for me the circuitry describe has functioned perfectly. If built carefully and correctly you should not have any problems. I do not wish to be held accountable for improper construction or short circuits.