Multispectral Imagery of Jupiter and Saturn Using Adaptive Optics and Acousto-Optic Tuning

Abstract

We obtained near-infrared, multispectral imagery of Jupiter and Saturn during July 1994 using the second-generation, laser-beacon adaptive optics 1.5-m telescope facility at the USAF Phillips Laboratory Starfire Optical Range (SOR). The telescope optics were equipped with a fast, germanium array and image correlation processor for tip-tilt correction on extended, i.e., planetary objects, and a broadband CCD "scoring" camera with 0.089 arcsec/pixel sampling, for evaluating the overall system performance. Wavelength tunable imaging was accomplished by sharing the focal plane with a Goddard-built, acousto-optic tunable filter (AOTF) camera operating from 700 to 950 nm. Spectral images of the Jupiter-SL/9 collision sites were photometrically calibrated and reduced to absolute reflectivity (I/F) at each wavelength. Images of the sites show spectrally dependent details which provide the starting point for one-dimensional plume models. Higher quality images of Saturn were acquired, with a spatial resolution of 0.29 arcsec. We attribute this to robust tip-tilt correction made possible by the presence of Saturn's rings, which break the symmetry of an otherwise nearly circular image. The compensated images of Saturn indicate early evidence of a northern hemisphere atmospheric disturbance.