The Telescope Drive Master with Controller v.2.5 and Encoder from Explore Scientific attaches to your equatorial mount and reduces the inherent drive errors while increasing tracking accuracy to as much as 1 arc-second. A mount-specific adapter is required to install it onto your mount, and is sold separately. The Telescope Drive Master (TDM) uses a high-resolution encoder and an electronics package to eliminate the need for Periodic Error Correction (PEC) training. For errors beyond PEC, the TDM allows auto-guider input as well to further increase the tracking accuracy.
The TMD electronic controller unit compares the incoming signals from the high precision rotary encoder, which is mounted onto the RA shaft, with the time signal of its quartz oscillator. Any deviations of the angular velocity of the RA shaft from the prescribed drive rate are compensated by feedback regulation in real time by accelerating or slowing down the drive.