The old method to compensate for residual periodic encoder errors using raw autoguider data caused too much noise resulting in sudden variations in tracking rates. A new method was developed which fits a periodic signal to the autoguider data to smooth its contribution and avoid sudden variations in tracking. Currently data is being collected which will be used to verify if the new method works and we will have to decide on how the corrections will be applied precisely.

Thomas Augusteijn 2008-01-11