First, all the attitude files are merged. Then the merged attitude file is read with the attitude FTOOL. Finally, the output of attitude is interpreted by the aspect STOOL. aspect bins the attitude points into 0.01 degree bins. It then finds the most populous group of four adjacent bins and calculates the mean pointing among those points. The aspect point is stored in the job.par for later use in both celestial and galactic coordinates.
Next, it runs the fixatt STOOL on all the attitude files. This tool deletes records which are out of time order (giving an error when it does so) and interpolates linearly between widely spaced attitude records. The interpolation is needed since the ascaexpo FTOOL does not interpolate between records.
FTOOLS called: