Thursday, June 3, 2010

Lunchtime 3-D Walk

It has been a little hectic at work, but I can usually take a leisurely lunch when the early and late shifts have an overlap and I can get away. It had been almost a month and a half since I'd dropped into the optics shop at the Optical Sciences Center (OSC) and checked on the Discovery Channel Telescope. I had a blog entry shortly after it was declared finished, and they were planning for shipping at that time, but hadn't heard anything since.

So with a little time to myself at lunchtime, I paid a visit and of course, was told "I should have been there yesterday"! The mirror had been suspended in midair as it was installed into the shipping box, so all I saw today was the steel box sections being installed around the primary mirror. But it is always interesting to check out how such a fragile load is shipped. The finished telescope mirror, not yet coated with it's eventual aluminum reflective layer, was instead covered with a blue protective coating that is easily removed once safely delivered. This mirror is quite thin for such a large diameter, so is supported by several large compliant disks on it's rear surface. The yellow shipping box has some huge steel cables that are coiled into springs. The stiffness of the cables translate into spring dampening in all directions if the box base gets a shock. And tracking it all the way is an electronic monitor that runs for several days recording how carefully it was handled on it's trip. There are two of them for redundancy.

The mirror ships next week, the trip to the telescope dome in Happy Jack, Arizona expected to only take 1 day. The box will be uncovered and the mirror carefully inspected the next day to assure no damage took place on the drive. The 3-D stereo pair is viewed by the cross-eyed method - check my first 3-D post for viewing hints.

After leaving OSC, it is only a brief walk across the University of Arizona mall to the Flandrau Science Center, where a couple 3-D targets presented themselves. First up is a sundial installed a few years ago by artist John Carmichael. The shadow of the ball mounted on the brass cable falls on the scale etched into the base plate. The time is read most accurately when the shadow crosses the hour marks, which has the figure-8 analemma that corrects for the "equation of time" which takes into account the elliptical orbit of the earth that make sundials run slightly fast or slow during various times of the year. I just happened by a minute or two past noon. hard to read in the wide shot, but is more evident in the blow up version...

And of course, Flandrau has always displayed a large meteorite near it's entry. This one is a iron meteorite that shows the fluted surface formed by air friction as it entered the earth's atmosphere. Flandrau has recently reopened to the public after a few months of closure. If you are in Tucson, be sure to stop by and support your science center!

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