Clearly, the most vital part of the CCD package is the combining of multiple exposures of calibration or science frames into a master frame. Therefore, before the actual processing is done, the calibration frames should be created first. The command that takes care of combining the calibration frame in the CCD package is COMBINE/CCD. It provides various methods to improve the S/N statistics in the resulting output frame. Dependent on the actual parameter setting, the combining process the command can take into account the exposure times, and can adjust for a (variable) sky background.