PDS_VERSION_ID                  = PDS3
RECORD_TYPE                     = STREAM

DATA_SET_ID                     = "HST-S-WFPC2-3-RPX-V1.0"

OBJECT                          = TEXT
  PUBLICATION_DATE              = 1998-07-17
  NOTE                          = "Abstract to HST proposal #6030, as
downloaded from http://presto.stsci.edu/public/propinfo.html in July
1997."
END_OBJECT                      = TEXT
END

                 CLOUDS AND AEROSOLS ON SATURN AND URANUS
                            HST Proposal 6030

Title:                 CLOUDS AND AEROSOLS ON SATURN AND URANUS
PI:                    TOMASKO (LUNAR AND PLANETARY LAB)
Category:              SOLAR SYSTEM
Cycle:                 5
Continuation ID:
Status:                completed
                                 Abstract
Our goal is to determine the vertical and horizontal distributions, and
the optical and microphysical properties, of aerosols and clouds in the
atmospheres of the outer planets. This information is needed to understand
the roles of aerosols in forcing atmospheric circulation and particle
microphysics. To achieve these goals we propose to acquire WFPC2 images of
Saturn and Uranus in the UV, visible, and near -IR methane and continuum
regions. UV and blue images provide vertical sounding of the absorptive
part of the aerosol opacity, critical for heat-balance studies, while the
methane bands give information on the scattering part. The combination of
the two provides an estimate of particle size from the wavelength
dependence of the opacity. HST observations are critical because (1) UV
images can only be obtained by HST, (2) the high resolution provided by
HST is required for center-to-limb coverage, and (3) of existing space
observations, only HST provides a suitable wide range of filters.
Observations taken during Saturn's ring-plane crossing in 1995 permit
superior imaging of both hemispheres, especially in methane bands. New
observations of Uranus can take advantage of the improved geometry for
center-to-limb observations. This proposal is similar to one originally
selected for Cycle 1 (program number 2564) for the outer planets that had
to be limited to Jupiter and Saturn due to the degraded performance of the
original HST optics.