8 Data files

8.1 Filenames and locations

At UKIRT, raw data files are stored in /ukirtdata/raw/uist/YYYYMMDD/ (where YYYYMMDD is the numeric UT date). The files are stored as Starlink HDS (SUN/92) containers (files with multiple data arrays). Each file contains one observation, and as such contains a header component and one or more integrations. Each integration is stored as an NDF component (single data array) of the HDS file. The raw filenames are uYYYYMMDD_NNNNN.sdf where NNNNN is the observation number, padded with leading zeros when necessary.

Reduced data files are written to /ukirtdata/reduced/uist/YYYYMMDD/ or $ORAC_DATA_OUT. The filename structure is: uYYYYMMDD_NNNNN[_(SUFFIX)].sdf for reduced observations, and guYYYYMMDD_NNNNN[_(SUFFIX)].sdf for reduced groups. The observation number (NNNNN) is not zero-padded for reduced groups, but is for reduced observations. The suffix is used by individual primitives (think of a primitive as a single step within a recipe) for their output files. The pipeline keeps track of passing these files between primitives; useful ones are left on the disk at the end so you can look at intermediate data products if you wish (these are marked in the table below). For example, u20021031_00123_ff.sdf would be data from a single observation, number 123, that has been flat fielded (the table below tells you that _ff means flat fielded). Reduced files can have either HDS (multiple data arrays) or NDF (single data array) format as appropriate.

8.2 File suffixes

Frame suffixes

Group suffixes