Apertif is a phased-array feed system for the Westerbork Synthesis
Radio Telescope (WSRT), providing forty instantaneous beams over 300
MHz of bandwidth. This data release includes the catalogue and image
observed by Apertif covering 26.5 square degree region in the Boötes
constellation at 1.4 GHz. The image is a mosaic of 187 Apertif images
from 8 different survey observations performed between April 2019 and
November 2021. It has an angular resolution of 27×11.5 arcseconds and
a median background noise of 40 μJy/beam. From this mosaic, 8994
sources were extracted and the catalogue is complete down to the 0.3
mJy level. This service queries the mosaic image of the Boötes field.
