SWUIS Hale-Bopp Shuttle Experiment Requests Supporting Hale-Bopp Observations in August

During the upcoming flight of STS-85 in August, NASA and the Southwest Research Institute (SwRI), along with scientific collaborators from JPL, APL, and the University of Maryland will be flying the SWUIS wide-field UV imager to observe comet Hale-Bopp. The primary objectives of the SWUIS Hale-Bopp Imaging experiment are to obtain image sequences of Hale-Bopp to study coma and tail morphology and response to solar wind conditions during the classical H2O-sublimation turn-off phase as the comet moves outbound beyond 2 AU. Observations are scheduled on 4 days during the 11-day STS-85 mission; STS-85 is currently set for launch on August 7.

SWUIS (pronounced, "swiss") is based around an 18-cm Maksutov UV telescope and a UV-sensitive, Xybion image-intensified CCD camera that frames at video rates (30 Hz). Each SWUIS observation period will last approximately 3 hours, and should garner 10^5 images in up to 7 filter bandpasses.

SWUIS will be operated from a 2-axis mount inside the Shuttle mid-deck cockpit, and looks out of the Shuttle through a quartz window. SWUIS can be pointed anywhere in a 4.5 deg cone around the centerline of the comet. Mission specialists will set up and operate the instrument.

The SWUIS imager's focal length can changed made during operation to allow the instrument field of view to range from 0.1 to 0.6 deg. The characteristic resolution of the SWUIS instrument is limited (by the CCD) to ~3 arc-sec. Comet imaging interference filters are being carried to make observations in the UV OH (0-0) and CS (1-0) bands, the UV continuum, the visible CN (0-0) band, and in other visible channels including the C2, CO+, and H2O+ emissions prominent in comets. Filter choice, camera gain, and filter integration times will be based on the data S/N being obtained.

The SWUIS science team (A. Stern, D. Slater, J. Parker [SwRI], M. A'Hearn {U. Md.}, L. Paxton {APL], P. Weissman [JPL]) requests collaborative observations of comet Hale-Bopp from groundbased observatories during the flight of STS-85. Spectroscopic, imaging, and polarimetric observations are all of interest during the period 5--21 August 1997 (or later, as appropriate, if the STS-85 launch is delayed). Communication between groundbased collaborators and the SWUIS team will be maintained through both the SBN email burster and also the SWUIS web site at http://www.boulder.swri.edu/swuis/. As SWUIS gathers data, coadded images will be placed on the SWUIS web site.

Those interested in making collaborative groundbased measurements during the SWUIS flight epoch should contact the SWUIS Principal Investigator, Alan Stern, at the Southwest Research Institute, 1050 Walnut St., No.~426, Boulder, CO 80302, or at astern@swri.edu.