Lat. Long. equation of time, and the solar compass

surveyor

Well-Known Member
#1
There is a remarkable instrument developed by a surveyor named William Austin Burt, patented in 1836, which was able to determine astronomical north from the passage of the sun, called a solar compass. It built upon the determination of longitude, using the equation of time developed with an Ephemeris. It is my understanding that he also made a prototypical typewriter also to aid in his survey maps. here are two videos that demonstrate both concepts about the solar compass.


 

JeffGu

Well-Known Member
#4
Solar compass schmumpass... they make lousy multicenders. But if somebody was to leave a BDB in a geocache in the remote wilderness, and your GPS was on the blink, you could whip out your 40 pound solar compass and home right in on it!

I don't recall ever seeing a solar compass at a garage sale or a flea market, however. Burglarizing museums seems a bit risky.
 

surveyor

Well-Known Member
#5
I would love to own one, but they are very rare and expensive (like the Bone : ). I tried to make a solar compass attachment on one of my old total stations, with only limited success. You can however, with a solar filter, sight the limb of the sun , and knowing your lat., and making a note of the precise time of observation, with the aid of an Ephemeris table, determine astronomical north.

http://www.cadastral.com/2013jan.htm
 
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