Name: Rex W.
Status: Other
Age: 40s
Location: N/A
Country: N/A
Date: March 13, 2004
Question:
I am trying to determine the approximate year a map was
made. The center point for navigation is latitude N 33.4360 and longitude
W 111.3580 The map indicates a North Pole of 8 degrees. Can you tell me
which decade between 1780 and 1950 comes closest to 8 degree variance?
Replies:
Rex,
There is a declination calculator at www.ngdc.noaa.gov/seg/potfld/declination.shtml, but
it only goes back to 1900.
However, considering how the declination was changing previous to about 1930, it would
appear to me that the declination was around your 8 degrees East somewhere between 1780
and 1820.
You may be able to find more precise information somewhere on the Internet if you look
around a bit.
David R. Cook
Atmospheric Research Section
Environmental Research Division
Argonne National Laboratory
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