Many CCD cameras
that make good autoguiders do not have outputs for controlling a
mount. There are also software protocols for driving the guider
inputs of mounts that are dependent on good real time performance
from the operating system (something that most desktop operating
systems are not good at).
I have built
a simple device that accepts commands across a serial port and translates
them to relay signals to guide a mount. Two protocols are supported.
The first emulates an interface sold by Starlight
Express. This protocol depends on the host computer for its
timing accuracy, since relay on and relay off commands are sent
separately. The second protocol was developed for some instrumentation
at Mt. Stromlo
Observatory and manages all of the timing within the controller.
In order to
use this device, you need to use a guider control program such as
that supports the SX or Mt. Stromlo com port driven interface.
This is a
simple board that uses an inexpensive Atmel microcontroller. All
the parts are available from Digikey
for about $20.