Simultaneous Observations of the Jovian Auroras using Juno-UVS and HST-STIS during Perijoves 4-7

NASA's Juno spacecraft has been in a highly elliptical, 53-day polar orbit around Jupiter since July 4, 2016. During each close encounter with the planet, the Juno-UVS ultraviolet spectrograph obtains unprecedented views of the ultraviolet emission from both the northern and southern auroras. During several of these perijove passes, the auroras were simultaneously observed with the Hubble Space Telescope (HST) using the Space Telescope Imaging Spectrograph (STIS) camera in time-tagged imaging mode with the F25SRF2 filter (130-182.5 nm) as part of HST program GO-14634 (Grodent et al.), which consisted of 151 HST orbits allocated for observing the Jupiter system in the UV (both the Jovian auroras and satellites). While these observations span a large range in time during late 2016 and 2017, this work reports on a subset of this data when Juno-UVS achieved spatial resolutions comparable to those of HST. The unique viewing geometry of Juno-UVS from high above both poles can then be directly compared to the simultaneous high emission angle HST observations. We compare the morphology of the auroras as seen by Juno-UVS and HST-STIS, and also estimate the auroral brightness and total emitted power observed from these two very different vantage points.