eROSITA

eROSITA (for Extended Roentgen Survey with an Imaging Telescope Array) is a German space X-ray Wolter telescope which is one of the instruments on the Russian Spektr-RG (SRG) space observatory. Its primary function is an all-sky astronomical survey called eRASS (for eROSITA all-sky survey) covering up to 10 keV (photon energy), aiming to observe the effects of dark energy. It began operation in 2019 with the launch of SRG, but in early 2022 with advent of the Ukraine war, German/Russian cooperation with ceased and eROSITA is presumed shut down.