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From: Alexandre Eremenko (no email)
Date: Sun Oct 17 2004 - 01:14:56 EDT
There are two separate related phenomena here.
1. Aurora Polaris, the lights in the sky.
They occur quite frequently and not necessarily
very close to the poles.
(The average number in New York is 10 per year).
The zone of highest frequency (about 100 per year)
in Northern hemisphere
spreads to N Lat 57d over Canada).
2. Magnetic storms. They occur at the same time all over the earth.
(This has nothing to do with polar regions).
The compass deviation during such a storm can be up to several
degrees and the storms last from few hours to several
days. They may also interfer with radio transmission, and some
say, even with electric power transmission.
Apparently there is a relation between both phenomena,
and they are caused by charged particles coming from the Sun
and interfering with the Earth magnetic field.
I do not know of any specific directions for navigators how
to deal with magnetic storms, except the general recommendation
of Russian manuals to determine compass correction by
astronomical observations every day (usually by sunrise and sunset).
Alex.
On Sun, 17 Oct 2004, Lisa Fiene wrote:
> The northern and southern auroras occur when electrically charged
> particles from the sun interact with our earth's magnetic field.
>
> Just a question, if one were to sail in these latitudes during these
> episodes of increased solar activity & the subsequent auroras these
> would create, would it affect the ship's compass at all?
>
> I've always considered this a likelihood, however never having sailed to
> these high lats, have never been able to test it.
>
> If it is the case, how do/did sailing vessels allow for this in their
> navigation?
>
> Thanks, Lisa
>
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