An EPIC MOS Auxiliary file (*M[1,2]*AUX.FIT) is created for each exposure in which at least one CCD node is producing either timing or imaging mode data. Each file consists of a single binary table. A single file per observation is created, where each row is labelled according to the relevant frame and CCD. The binary table consists of the columns listed in Table 6.
| Name | Type |
Units | Description |
| FRAME | 1J | COUNTER | Frame number |
| CCDID | 1B | CCD identifier | |
| CCDNODE | 1B | CCD node identifier | |
| FTCOARSE | 1I | SECOND | Coarse frame time |
| FTFINE | 1I | 40 s |
Fine time frame |
| NPIXEL | 1J | PIXEL | Pixel count |
| NVALID | 1I | COUNTS | No. of valid events |
| NBELOW | 1I | COUNTS | No. of events rejected by lower thresholding |
| NABOVE | 1I | COUNTS | No. of events rejected by upper thresholding |
| GATTIFLG | 1B | Gatti flag | |
| FIFOOVF | 1B | FIFO Overflow Flag |
See Sect. 9 for convention