ABSTRACT
The autoguiding process is a repetitive loop. There are two main camera styles in common use for autoguiding; low-noise, sensitive CCD cameras. An inappropriate choice of guider hardware adds further sources of noise to ones' base system, mostly in the form of differential flexure, guide star definition and optimal guide star selection. Maxim DL has the option to apply a full image calibration to guider exposure. The tracking graph in the top left window shows several versions of the data. These are light grey for the actual tracking error, dark blue for the periodic error (PE) without the drift, green for the noise and red for the filtered and smoothed error resulting from the worm drive in the mount. Periodic error and its control have been mentioned a few times in passing but so far not in any particular detail. Mount systems have a mechanism to store a set of PE correction values for each worm angle.
