April’s ASKAP update describes plans to resume survey operations and assess the performance of Setonix as the new data processing platform, summarises a new ASKAPsoft release, and gives details of an investigation into ASKAP’s astrometric accuracy. The figure above shows the average astrometric errors with respect to the RACS-low catalogue for a series of VAST epochs taken during full survey observations over the last few months. The offsets are usually less than the indicated 2 arcsecond level, but poor weather conditions can cause more rapid departure from the phase solution of a given bandpass observation, leading to larger errors on occasion. The 2 arcsecond accuracyis due to the fact that with ASKAP’s wide field of view, we currently do not phase reference in the same way that single-beam interferometers typically do. Regularly placing a phase reference source in each beam one by one would add significant overhead to ASKAP observations. The Update describes several other options that are under consideration. (Image credit: Emil Lenc)