Files names and extensions used for FOC (X)

The name of each file in an FOC dataset, such as x3l80101t.d0h, has a three-character suffix, in this case the d0h, that uniquely identifies the file's content. When an FOC image comes down from the telescope, it is stored in files with suffixes .d0h/.d0d. The image is then automatically calibrated to produce the .c0h/.c0d and .c1h/.c1d files. The .c1h/.c1d files contain the final calibrated data, which are likely to be of greatest interest to observers. The table below gives the various file suffixes for the FOC and the corresponding file contents, listing all of the files that the pipeline can produce. Not all of the processing steps are performed for every observing mode, so only a subset of these files may be available.

In addition to the image files, the .trl or trailer file—which comes with each FOC observation—is an ASCII text file that describes the standard processing applied to the images by OPUS. The .pdq file reports any real-time activities associated with the observation, such as slews for an interactive acquisition, and any problems that might have occurred with the telescope, such as a guide star acquisition failure or guide star recenterings. The standard header packet (.shh and .shd files) contains information about the scheduling of the observation. The data quality files (.q0h and .q0d), in principle, would contain information on position of blemishes in FOC images. However, they are not used by the FOC because these positions vary with time, limiting the utility of these files. The unique data log files (.ulh and .uld) contain engineering information not generally of interest to most observers.

The FOC suffixes