Titan's atmosphere in late Southern spring observed with adaptive optics on the W. M. Keck II 10-meter telescope

Using adaptive optics on the W. M. Keck II telescope, we imaged Titan several times during 1999 to 2001 in narrowband near-infrared filters selected to probe Titan's stratosphere and upper troposphere. We observed a bright feature around the south pole, possibly a collar of haze or clouds. Further, we find that solar phase angle explains most of the observed east-west brightness asymmetry of Titan's atmosphere, although the data do not preclude the presence of a 'morning fog' effect at small solar phase angle. Key Words: Titan; satellites; atmospheres; infrared observations.