High Resolution Encoders
ASA mounts have high precision incremental encoders on both axis to measure the position & movements up to hundred times per second.
That way, the IS and SHOULD Position can be corrected in real time. Because of the internal direct drives, these corrections can be made on both axis in any direction at very high speeds.
The Renishaw absolute encoders have 0,02 arc second resolution. No homing and no loss of position after power failure with absolute encoders.
From 2016 all mounts have absolute encoders