A Tail of Two Giants: Observations of Saturn’s FUV auroras in Jupiter’s magnetotail

In late November 2020, Saturn passed through the projected location of Jupiter’s magnetotail. No other planet experiences such an event, which occurs for Saturn once every 19 years. It presents a unique natural experiment to capture the behaviour of a planet’s magnetosphere under such unusual conditions. We report on the results of a programme of Hubble Space Telescope observations of Saturn’s UV auroras, which provide an indication of the state of the magnetosphere, during this interval, and compare the auroral morphology with projections of the solar wind and location of Jupiter’s tail.