Apertif is a phased-array feed system for the Westerbork Synthesis
Radio Telescope (WSRT), providing forty instantaneous beams over 300
MHz of bandwidth. A description of the second data release is to be
included here. The raw visibility data are provided as separate
collections for the survey fields, flux calibrator and polarization
calibrator observations. The tables can be joined to identify the
associated calibrators for a target observation. This service queries
the raw visibilities for the survey fields. These are stored on tape
and are not immediately available for download. The data release
documentation should be consulted for up-to-date information on how to
access the data.