First ground-based adaptive optics observations of Neptune and Proteus

High angular resolution (0.15″) K-band images of Neptune were obtained in August 1995, with the University-of-Hawaii adaptive optics system mounted on the 3.6m Canada-France-Hawaii telescope. The images show bright high contrast features that are believed to be high altitude clouds. They confirm that low latitude (<30°) cloud activity has shifted since Voyager from the south hemisphere to the north hemisphere, whereas higher latitude activity seems more permanent. Proteus can be seen at the locations predicted from Voyager data. Its K-magnitude is 19.0±0.03. The corresponding geometrical albedo is identical to that measured in the visible by Voyager.