Cosmic Beacons

Every night, a variety of astronomical objects flicker or explode. We are becoming quicker at catching these transients, but we only have blurred images that do not yield any physical information. To get it, we need rapid follow-up spectra, which are usually expensive and on over-subscribed instruments on large telescopes. Here, I propose to recommission and upgrade the spectroscopic mode of DFOSC, a simple and robust instrument on the Danish 1.5m telescope (already refurbished and hosted at an ideal observing site), to enable the immediate characterisation of every transient that we detect in our surveys. This project will be right on time with the advent of the Vera Rubin Observatory, the most ambitious multi-epoch imaging survey by the astronomical community, with “first light” due in 2022-23.