OFJ Field Journal from Glenn Orton - 11/27/95
FASTER AND FASTERSince the Mauna Kea observing (on Hawaii's Big Island), things seem to have taken on a rapid pace whose toll on me I'm trying to slow down. I can't believe that we have so little time to spend on preparing for the data before it comes in!
Jose Luis and my colleague on the Galileo Photopolarimeter- Radiometer (PPR) experiment, Terry Martin, made another trip to the NASA Infrared Telescope Facility at Mauna Kea. Despite some bad weather conditions, they did well, working only on NSFCAM, the near-infrared camera which is mostly sensitive to sunlight reflected from Jupiter's clouds (rather than to planetary heat from the interior of the planet itself).
While they were there on Nov. 17-21, I tried to get some of their files at JPL and look them over to make comments and suggestions. One of those nights just didn't work out well. I had a breathless call from my wife on Nov. 21, saying she had to take the kids to the piano lesson in the car I intended to use (we took both cars in - she's been visiting her mother at the hospital each morning). The other one had a flat tire! Oh, this was NOT what I needed at all. By the time I finished getting the Previa re-wheeled, it was quite dark and I was working by flashlight. I don't think I've changed a tire for more than 20 years; it would feel good to know that I can still do it alone, if it were not for the fact that my arms were totally sore and almost 2 hours went down the tube! I got the tire repaired (where a large nail was plainly visible in the puncture) the next day at a store within a short shuttle ride from JPL. But when I waited for the shuttle at the end of the day, it was 20 min late - there was a fire in a building a block away from the tire store. It took another 50 min. to get there and get out, where my mother was waiting at home along with my wife and kids. All were impatiently wondering what took me so long; they wanted to take Linda's father out for supper and it was getting late for a Wednesday night before Thanksgiving (when absolutely no one cooks dinner at home who's cooking the next day). My mother was visiting for Thanksgiving.
Friday night, Padma Yanamandra-Fisher, another colleague in our group, was at the IRTF to get images of Saturn just after the rings crossed through the plane of solar illumination. She wanted to see how fast the newly lit sides of the ring particles would heat up. Although she was working through clouds, she did manage to get a few good 5-micron images of Jupiter with NSFCAM. At this wavelength, we are looking at thermal (heat) radiation from Jupiter, not reflected sunlight, because sunlight is so weak at this long wavelength. I've been tracking Jupiter's appearance at this wavelength, because it's sensitive to temperatures at Jupiter's cloud tops.
Padma's data represent almost undoubtedly our last look at Jupiter at 5 microns without a polypropylene solar protective cover which we'll use in early December. The cover will severely restrict the type of data we can get at 5 microns: it won't let much of it pass through, and it won't let ANY of the reflected sunlight at shorter wavelengths through. I had a phone call from Bob Joseph, the IRTF Director, explaining why he decided NOT to allow us to use a new configuration for the screen which would have let more of Jupiter's light through - it would have been at the forward part of the telescope and possibly could have ripped apart in the wind, with disastrous results for the instruments it was supposed to be protecting.
I spent a little time at JPL on Saturday morning, mostly before my family woke up, going over the data from the observing runs and trying to map them onto a mercator (cylindrical) disk projection, and THEN trying to move them forward in time to see what they might look like at the longitude of the Probe entry site. I found that there is still a bit of uncertainty as to whether the area is clearer or cloudier than "typical" regions in other places at this latitude and elsewhere on the planet. I also discovered that there were some places where the data didn't make sense, and I have to try to see whether there are mistakes in the way I processed the data.
This morning, while the kids and my mother and I were at church, Linda left for Kitt Peak - an observatory just outside Tucson, Arizona, where she'll make laboratory spectroscopy observations of gases. She will get back on Wednesday night, and I'll fly out on Thursday morning for the final stretch of observations before Probe entry.