OFJ Field Journal from Glenn Orton - 11/6/95Blue sky everywhere. Dare I hope?
I talked to the crew managing operations at the telescope this morning and early in the afternoon; we had to figure out how (if we can) make observations in the near-infrared when we're very close to the sun at the time of the Probe entry next December.
A series of tests showed that near-infrared observations will be impossible: the sun always shines on the center of the IRTF's primary mirror, right at the spot where the aperture (circular opening) which allows light to pass through the primary to the instruments seated beneath it. But the IRTF Chief, Dr. Robert Joseph, is there and we discuss the alternative plans for covering the telescope primary: instead of putting the polypropylene cover right over the primary, deep in the telescope (where light will have to make three passes through it), we can put it up at the front of the telescope and cover the sides with black polyethlyene. So we cover the front of the telescope with potato chips bags and the sides with trash bags (almost literally - it's the very same types of plastic material). Bob is still worried about the health of the instruments.
We start observing in the afternoon. The quality of the images is not so good, as the spectacular ones in the yesterday's late afternoon, but we've avoided huge cumulus clouds pushed up the side of the mountain by 3 PM, so we're getting something. This is an area of Jupiter which we didn't observe yesterday for the most part. We finished a little later, after crashing the computer system which runs the camera - by trying to save an immediately viewable file - I won't do THAT again! We got a bit of data in the near-infrared with another instrument. Then, we were changing instruments back again to view Jupiter on the one side we didn't get, when the wind picked up and blew clouds right in over the summit. Freezing fog that didn't let up at all until just after midnight (so we were told later).