Mathis MI-750 Dual-Axis High-Res Encoders
These ring encoders provide .10 arc second resolution on each axis. They have typical error profiles of plus/minus 4 arc seconds over 360 degree (pointing error over the entire sky) and short term errors (tracking errors) of plus/minus .20 arc seconds. Even these small errors can be modeled and reduced. Using Renishaw encoders on each axis, the mount position is determined by these master encoders rather than the mount's drive gears and motor encoders. For use with the Servo II control.
Mathis Instruments Product Number: 750-HRE