Hugh,
Thanks for publishing the pertinent article by KT entitled, “Time OUT”. Timing and coordination with other group members can and will be very critical ability in the future. Many of us grew up watching old World War 2 war movies, and this article reminded me of memorable scenes from some of these classics, to-wit: a scene with a bombing group having a pre-raid briefing and the closing of the meeting would conclude with the commanding officer having all pilots and crew members “setting” their watches. This was done by a “hacking” mechanism in the watch movement. One can pull out the stem and the movement stops. This allows everyone in the group to reset their watches to the exact same time. A hack feature is still available in many mechanical movements and would be an added benefit to coordinating group activities that, by their nature, might require precise action…down to a matter of single seconds. Again, a most excellent submission by KT!
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Hugh,
The shadow from a plumb bob passing over a meridian line can get you local apparent solar noon to within +/- one minute of accuracy. A special tool called a theodolite should get you better accuracy. The following articles discuss some of these techniques:
- http://www.precisionsundials.com/compendiumarticlefindnorth.doc
- http://books.google.com/books?id=uYz4ODJ5XhsC&lpg=PA347
Then use a table based on the equation of time for your location to determine how many minutes to add or subtract to adjust solar (sun dial) time to your local standard time.
RLH in Ohio
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HJL,
I came across instructions on how to make your own star clock. I have not tried it yet, but it does seem useful. – JC in TN.
HJL Replies: I was intrigued enough that I printed the parts out on my printer and assembled it. It does indeed work. Now if I could only find one of these in durable plastic or metal.