Detection of Flash from fragment R at McDonald Observatory
We observed the impact of fragment R. We were fighting clouds the entire night. There was a somewhat clear spot during the predicted impact time. Continuous integrations were made with ROKCAM on the 2.7m telescope in the H2 filter at 2.12 microns, with the CCD camera on the 0.8m telescope using a 893nm filter, and with a low resolution CCD spectrograph on the 2.1m telescope. A brightness was first noticed on the east limb of Jupiter at 5:35UT with ROKCAM but we believe this was the impact spot from Q rotating into view. At 5:41:36 UT a dramatic brightening was observed on the east limb with ROKCAM. The spot had brightened by a factor of 2 in the 18 seconds between consecutive images. The flash saturated the detector, and we had to cut down the integration time by a factor of 5. About 20 minutes after the flash, the clouds rolled in again.
In contrast, the 0.8m CCD images do NOT show any obvious brightening at the same time, nor did the CCD spectra from the 2.1m. However, all of the spots from the previous impacts were clearly visible to both CCD instruments. This lack of clear detection of the flash at 893nm and the upper limits we will be able to place on the brightness from the time-resolved CCD spectra will enable us to constrain the temperature of the fireball.
Images in GIF format will be available on WWW as soon as we can do a quick processing.
The McDonald Comet Impact Science Team