BIGCAT is the new GPU-based correlator for ATCA. After installation and engineering commissioning finished, science commissioning began in August, with a team of astronomers putting the telescope through its paces. As expected, this revealed a number of bugs and issues which the BIGCAT team were quick to fix. The image above, from a BIGCAT Update given at September’s ATUC meeting, show a selection of images from the science commissioning observations. Clockwise from top: the image of an HII region and spectrum showing a radio recombination line, the image of two radio stars belonging to the class of Main-sequence Radio Pulse emitters, the spectrum of the water vapour maser in the Galactic HII region W49, and the detection of a gamma-ray burst afterglow. The ATCA has been offline from Sep 1 for work on antennas as part of the ATCA infrastructure upgrade. Scheduled observing in the BIGCAT era will start on Oct 20th.