Recent developments in widefield radio telescopes have enabled searches of a new region of parameter space in the time domain: timescales of seconds to minutes, that have been overlooked in traditional surveys. These searches have revealed a new population of sources: long period transients, which typically show periodic behaviour of minutes to hours. In addition they have detected phenomena ranging from extreme scintillation to stellar radio bursts. However, almost all searches to date have involved archival data that has been processed in offline, batch mode. In this context, Wang et al. present VASTER, the first short-timescale imaging and transient detection pipeline running in real time on a widefield radio telescope. VASTER has been running on ASKAP since July 2025, and images most of the ASKAP survey project data on timescales of 15 minutes. Results from the first two weeks of operation include the discovery of two long period transients: ASKAP J165130.3−450520 with a period of 6.48 hours and ASKAP J170036.6−445758 with a period of 4.69 hours. The detection of these two sources adds to the small, but growing, population of long period transients, as well as demonstrating the potential of VASTER to explore this region of transient parameter space.

The image above shows light curves of other detected transients (i.e., excluding the two long period transients) in their detected epoch. Source identifications are given in the bottom-left corner of each panel, with detections of 2 AGN, 9 known pulsars, 6 flare stars, and 2 unidentified sources.  The two unidentified sources are shown on the bottom row, and have no label.