Last night was our springtime Star-B-Que at the Kitt Peak picnic area. We've had some spectacular ones in he past - great skies and a nice venue with a pavilion and tables for a sizable group to socialize and picnic. Since the Tucson Amateur Astronomy Association (TAAA) assists Kitt Peak National Observatory with some of their outreach events, they even let us use their grill for the cookout. Unfortunately, the weather leading up to the weekend was not promising, but the Clear Sky Chart was hopeful for late clearing, so always the optimist, I prepared for clear, but always enjoy the trip, rain or shine!
Sure enough, the promised clearing was a hoax, but there were some spectacular cloud buildups and long lines of rainstorms visible out in the desert, so lots to watch for. Of course, clouds and vegetation always looks more impressive with my IR-modified camera, so used it for the 3-frame mosaic of the radio dish and mountaintop shown at left here. The radio antenna is part of a 10-dish array scattered over the hemisphere, the Very Large Baseline Array. Using the signals from all of them, they can synthesize maps of an object as if they had a dish nearly the size of the earth! It was stowed when this picture was taken, but a little later it came to life and was working in the eastern part of the sky, as shown at right.
It is an interesting time of year on mountains of southern Arizona. The vegetation is dominated by scrub oak trees - considered evergreen, they keep their leaves through the winter, and the old leaves die off and are replaced by new growth this time of year. When pointing this out to the attendees, most thought the trees were stressed by drought, but in fact in a close examination you can see both old green leaves, some yellow/brown leaves, and the new growth of grey-green leaves. It was always interesting to get our "Fall" colors in the springtime on mountaintops!
Wood effect of infrared wavelengths - vegetation readily reflects IR light and the blue sky is naturally dark in IR.
Since we didn't have telescopes to set up with storms within 15 miles of us, we set up the grill, and in fact, gathered around it to get warm with the cool temperatures and blustery breeze. You could tell we were all thinking alike as a majority brought brats to grill and potato salad as a side dish! After dinner we mostly played a waiting game to see what the weather would do. At right a couple attendees keep an eye on storms towards Sells and beyond to the west.
Here is the time-lapse of some of the desert rain and sunset. You can watch it in this viewer or go to the YouTube site to watch it, or click it for full-screen. Watching it full-screen, likely requires going to the highest quality setting.
As I returned to the van from the outlook after the sunset, it started sprinkling, and by the time optics and cameras were put away, it started drizzling in earnest. All had left by this time, so we did the same. As I was locking the picnic area gate in the rain, I looked up and was able to see Jupiter high in the sky over the setting Winter Milky Way! We were THAT close to having clear skies, but the rain generally increases the humidity enough to cause dewing problems even if it had magically cleared right away. So it was an early evening at home, though the cats were glad as we got home to feed them at 9pm...
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