A beam director may take the form of a siderostat, or a Coude' telescope of Alt-Az,
Alt-Alt, or equatorial configuration.
DFM Engineering has built a Alt-Alt (altitude over altitude) beam director/Tracker (BD/T) with a 0.8 meter
aperture and a Coude' optical system.
This system is located at the US Air Force Maui Optical Station and has been used for many experiments.
We have also built two smaller beam directors of the altitude over azimuth (Alt-Az) Coude' configuration.
Coeleostats: A coeleostat is typically a siderostat,
but the word is poorly defined. The name may also be used to describe a beam director.