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Subject: The mil as a unit of angle.
From: George Huxtable (george@XXX.XXX)
Date: Tue Mar 11 2003 - 19:38:00 EST
Dour Royer said-
The use of a mil-compass is also needed.Mil does not
>> stand for military but mil:1,000th of something.The mil-compass is hand
>> held and has 6,400 seperate & equal segments in 360*.The compasses are
>> also known as lensatic compasses.You can get great accurecy in
>> distance,height and position useing the mil.
Response from George-
It's good that we keep on learning new things on this list. I had never
heard of the mil as a unit of angle, nor had I come across insertion and
resection in Doug's context.
However, it's rather mind-boggling to discover yet another unit of angle,
64,000 in one rotation! Presumably, this is to put compass "points" at
round-numbers of units. However, this convention shares many of the
awkwardnesses of our 360 degree system. It makes the heart sink, when
there's an obvious logical measure of angle just waiting to be adopted, the
Turn, to be subdivided into 1,000 milliTurns. When you go through one Turn
you get exactly back to where you started, so calculations involving angles
exceeding 1 Turn just require dropping the integer part. It's decimal all
the way, none of these nasty sexagesimals. Of course, it shares with all
other decimal units the disadvantage of not dividing easily into 8ths and
16ths and so on, as were used for compass "points". But we don't use
compass points much these days, courses and bearings are nowadays
understood simply as a number.
Of course, there are serious snags about making such a change. It would
require recalibration of all our charts, compasses, and sextants. Not for
the faint-hearted!
George Huxtable.
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contact George Huxtable by email at george@XXX.XXX by phone at
01865 820222 (from outside UK, +44 1865 820222), or by mail at 1 Sandy
Lane, Southmoor, Abingdon, Oxon OX13 5HX, UK.
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