They are used for target acquisition and attitude control, but sometimes their images are archived. The other four cameras are for spectra, but only three of them were ever really operational. Each camera has a name and a number, as shown in Table 1.1 . For each camera, every image has been assigned a unique Image Sequence Number. This number will have usually have five digits, zero-filled as necessary.
Data types vary with processing software, but generally several stages of processing are preserved.
First there are the raw data files. These files may contain data from either or both the large and small apertures.