  This document describes a convention for compressing FITS binary tables that
is modeled after the FITS tiled-image compression method (White et al. 2009)
that has been in use for about a decade. The input table is first optionally
subdivided into tiles, each containing an equal number of rows, then every
column of data within each tile is compressed and stored as a variable-length
array of bytes in the output FITS binary table. All the header keywords from
the input table are copied to the header of the output table and remain
uncompressed for efficient access. The output compressed table contains the
same number and order of columns as in the input uncompressed binary table.
There is one row in the output table corresponding to each tile of rows in the
input table. In principle, each column of data can be compressed using a
different algorithm that is optimized for the type of data within that column,
however in the prototype implementation described here, the gzip algorithm is
used to compress every column.
