FIRST GROUND-BASED ADAPTIVE OPTICS OBSERVATIONS OF NEPTUNE AND PROTEUS

High angular resolution (0.15 '') K-band images of Neptune were obtain ed in August 1995, with the University-of-Hawaii adaptive optics syste m mounted on the 3.6 m Canada-France-Hawaii telescope. The images show bright high contrast features that are believed to be high altitude c louds. They confirm that low latitude (<30 degrees) cloud activity has shifted since Voyager from the south hemisphere to the north hemisphe re. whereas higher latitude activity seems more permanent. Proteus cal l be seen at the locations predicted from Voyager data. Its K-magnitud e is 19.0 +/- 0.03. The corresponding geometrical albedo is identical to that measured in the visible by Voyager. (C) 1997 Elsevier Science Ltd.