The surface of Titan from NICMOS observations with the Hubble Space Telescope

From diffraction-limited images produced by the near-IR camera NICMOS aboar d the Hubble Space Telescope we derived maps of Titan's surface in the meth ane windows near 1.1, 1.6, and 2.0 mu m. Each part of Titan's atmosphere an d surface was imaged at least twice over a time period of 24 h to look for moving clouds. Despite careful analysis we found no evidence for cloud acti vity. On the contrary, we were able to reproduce most of the features ident ified by previous mapping efforts, indicating that the albedo landscape rem ained stable over several years and is most likely indigenous to the surfac e. At the 3 sigma level we confirmed two brightness peaks in the prominent, continent-sized bright feature on the leading side of Titan. Many smaller landmarks could be mapped, including distinct surface structures on the dar k, trailing side of Titan. These rule out the presence of a single large et hane ocean on the "backside" of Titan. No obvious differences could be seen between the maps at different wavelengths, other than a gradual loss of sp atial resolution due to the diffraction limit of the 2.4-m primary mirror. (C) 2000 Academic Press.