Figure 1.

The evolution of ice giant imaging from Voyager to the present day. The left column represents our twentieth-century views of Uranus(1986) and Neptune (1989) as observed by Voyager 2 (Credit: NASA/JPL-Caltech). The central column shows some of the best ground-based images of Uranus (near-IR from Keck in 2012, using high-contrast imaging to reveal the banded structure [10]) and Neptune (visible-light from VLT/MUSE in 2018, Credit: ESO/P. Weilbacher (AIP)). The right column shows the ice giants observed by the Hubble Space Telescope in 2018 (Credit: NASA, ESA, A. Simon, M.H. Wong and A. Hsu). Neptune’s southern pole has been in view throughout this 30-year period, whereas Uranus was in southern summer in 1986 (left), and northern spring in 2018 (right). (Online version in colour.)