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Subject: [Nml] theodolites
From: Paul Hirose (71202.2014@XXX.XXX)
Date: Sun Mar 28 1999 - 15:53:38 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.
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