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Theodolites
From: Paul Hirose
Date: 1999 Mar 28, 15:53 EST
From: Paul Hirose
Date: 1999 Mar 28, 15:53 EST
Someone on the list was looking for a theodolite but was having trouble finding a source. Well, I was strolling down Colorado Blvd. in Pasadena (Calif.) and noticed a military surplus shop with several theodolites on display in the front window. Didn't make note of the prices, unfortunately. Also, there are periodic auctions at Air Force bases and perhaps bases from other services as well. The Defense Re-utilization and Marketing Office at Edwards AFB has unloaded several theodolites, I learned. One was a Wild T-3 which went to "some guy from Alaska". I think there's a Web site for info on these auctions. Can get details if anyone's interested. I once had a job where I had access to a T-3. Didn't use it myself; we just stored it for the people who used it. On slow nights I would take it out to look at the Moon or just play with it. Beautiful instrument. No electronics. All opto-mechanical. It was Swiss, I think, and I'd guess it was about 1960 vintage. Etched glass circles for vertical and horizontal. All the works were enclosed and protected from dust and weather. You read the circles through a microscope whose eyepiece was right next to the one for the telescope. An optical micrometer read to a tenth second, although you had to develop an "eye" to get consistent readings. We may still have the manual at work. I'll have to look tomorrow. Nowadays we have four Wild T3000s on the shelf. These are electronic, also reading to .1". The calibration lab only guarantees them to 1", however. I think that's because their equipment doesn't go any finer. Normally the setup people use two or more T3000s at a time, all connected to a computer, but there's an LCD and control panel on the theodolite and you can use it stand-alone. This model automatically does many of the delicate, time-consuming alignments you had to perform on the old T-3 to prepare it for use. It's tremendously faster and easier to read. But for a personal plaything, I'd take the T-3. Plastic buttons and digital displays are no match for the chrome-plated knobs and doodads that seemed to sprout from all sides of the T-3! Even more fun might be one of the American-style theodolites you see in 1940s surveying books. Unlike the enclosed European types, these were "open" designs with big metal circles read by paired microscopes on opposite sides of each circle. I've never seen one of these in the flesh. You'd probably have to pay antique prices for one. There must have been lots in use decades ago. Wonder what ever became of them. =-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=--=-= =-= TO UNSUBSCRIBE, send this message to majordomo@XXX.XXX: =-= =-= unsubscribe navigation =-= =-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=--=-=