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Subject: Re: Planet rising revisited
From: Lars Tornqvist (lpt@XXX.XXX)
Date: Tue Feb 05 2002 - 17:55:47 EST
Hi Dave
All objects at their rising position are farest away (90deg or 5400 Nm
away) - meaning it's perfect for an azimut! Azimuts are used for compas
corrections.
You don't need the exact time for an exact azimut - and furthermore your own
position does not need to be exactly to obtain a good azimuth!
Two Objects which is 5400 miles away will have the same bearing within a
broard margin of position
Imagine that you are in London and could see the Statue of Liberty in N.Y
If you take a bearing of the Statue and walk south 5 miles the bearing will
still be the same or impossible to detect by your compas!
Nowadays we take azimuts with high precisions due to precise clocks and
knowledge positions etc.
The rise of an object in the old days was very important as the knowledge of
magnetic variation was poor or none - an azimut as often as possible was
certainly a great need those days!
Hope this will do.
Lars
----- Original Message -----
From: daveweilacher@XXX.XXX>
To: <NAVIGATION-L@XXX.XXX>
Sent: Tuesday, February 05, 2002 10:19 PM
Subject: Planet rising revisited
> What practical use would a navigator have for determining when a planet
would rise? (other than at twilight)
>
> Dave
>
>
>
> --------------------------------------------------------------------
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