This N That

In my post Sunday about our trip out of town, I showed a side view of a distant thunderhead, with a swath of rain below. Last night we had a closer, more oblique view. Right at sunset, as I walked out to get the mail, the rumblings of thunder woke me to the close proximity of this thunderhead that was certainly photo and blog-worthy. Even with the wide-angle lens (10mm) I could barely get the uppermost sweep of the cloud. No rain to report here...


With the end of the month upon us, the monsoons are also winding down and with them the forecasters promise of a wet summer storm season. The nightly weather dutifully reports we are upwards of 4" behind our normal annual rainfall, which doesn't sound like a lot, but is nearly half our yearly total! Of course, with the passing wet season brings with it the promise of clear cooler nights, and in fact, Jupiter shines brightly in our southeastern sky tonight, but after a long day at work (more about that in a sec...), no scope set up tonight. Of course, those of us living in the desert (even the astronomers!) would likely prefer a drenching rain, but it is looking more and more like that won't be happening anytime soon...


Today was high temperature day of the latest Mirror Lab casting - that for the San Pedro Martir 6.5 meter telescope. The day started early with representatives from this project's partners, from other current telescope projects, and dignitaries from south of the border (I spotted several from the mayor's office of Ensenada, Mexico). In this photo the Steward Observatory director, Peter Strittmatter, facing the camera in center, talks to attendees, with the spinning oven containing 11 tons of molten glass behind. At this moment (2130 local time) the oven is well past the peak temperature of 1165C to 1125C, and will continue to drop about 30 degrees/hour or more until the glass freezing point is reached at about 800C. The oven will continue to spin at 7.4rpm until 700C, which is scheduled for sometime Friday at the moment... Cooling slows considerably to prevent internal stresses from building, with the oven staying sealed until mid-November - a long time to wait for a cake to come out of the oven! I haven't heard of any issues or problems, not that casting these is routine yet. This is the 12th (by my count) casting over 3.5meters diameter and it still attracts a lot of attention!