Wed Jul 20 21:53:39 1994

FROM: SOR Comet Observing Team

SUBJECT: Report from SOR: Albuquerque, NM

On the 1.5-m, we were able to see the first transit of the L impact site in evening daylight at 07/20, 00:30 UT. In our visible, broadband camera it appeared as a central dark spot with a diffuse central ring approaching the CM. Apparent brightness comparable to the G/D complex seen toward the west limb. With the image correlator tracker loop closed the AOTF CCD camera (R=500) failed to detect either site at 890nm whereas they both appeared as dark patches at 830nm. We were able to monitor Jupiter southern hemisphere over approximately 5-hours.

Images were taken with the AOTF CCD camera at 725-, 760-, 790-, 825-, 890-, 900- and 950nm in strong CH4 and NH3 bands and adjacent continuum regions. Several complete sets of data were acquired with both the image tracker and the laser beacon adaptive optics loops closed. This provided sub-arcsec seeing which enabled us to identify all available sites at all AOTF wavelengths. Broadband CCD context images (plate scale 0.08-sec/px) were interspersed . Just before Jupiter set, we were able to identify the beginning of the 9th transit of the "A" collision site.

At the 3.5-m continuuing uncompensated observations in methane bands at 604-, 727-, 890-nm reveal same structure as noted above. Images at 2.35-microns were taken using a NICMOS III camera. These images clearly show identifiable impact sites against the dark background. Site "l" was observed during first transit and appeared brighter and more localized than neighboring sites.

SOR Comet Observing Team