We all know that True North (Polaris) is not the same as Magnetic North
when orienting a sundial. My grandfather's Boy Scout pocket Sunwatch is a
true gem for our family -- loaded with information for any enthusiastic
sundial traveler (complete with a compass, dial, and table of corrections
for
compute this variance for True North?
The anomaly is truly anomalous: it varies with coordinates relative
to the Magnetic Pole, but also with local geodetic anomalies, such as
large concentrations of iron; and over time as the M.P. floats
around. I doubt there is a formula, although
Hello Judith:
The Earth's magnetic field is in a constant state of change so there is no
simple answer to your question.
Every 5 years or so the World Magnetic Model is updated. This model will tell
you what the magnetic field is for a given location and date anywhere on the
Earth's surface
Judith,
Go to everyone's favorite search engine, Google.com, and enter
magnetic declination (or magnetic variation) and you'll find more
information, both text and graphic, than you can possibly browse
through before the end of this decade!
Cheers,
Mac Oglesby
We all know that True
Romano, Judith wrote:
We all know that True North (Polaris) is not the same as Magnetic North
when orienting a sundial. My grandfather's Boy Scout pocket Sunwatch is a
true gem for our family -- loaded with information for any enthusiastic
sundial traveler (complete with a compass, dial,
