|
|
Subject: Re: The mil as a unit of angle.
From: Brooke Clarke (brooke@XXX.XXX)
Date: Tue Mar 11 2003 - 20:32:37 EST
Hi:
In military artillery one mil is equivalent to 1 yard offset at 10,000 yards range.
It's not the lensatic compass, but the M2 pocket transit that comes in either Mils or degrees.
This instrument is currently made by Brunton in a number of versions and "Brass Comapss with a wooden box" imported repro versions
are all over the place. Interesting to me is that this instrument was pattented 1,571,697 by K&E
<http://patimg2.uspto.gov/.piw?Docid=01571697&homeurl=http%3A%2F%2Fpatft.uspto.gov%2Fnetacgi%2Fnph-Parser%3FSect1%3DPTO2%2526Sect2%3DHITOFF%2526u%3D%2Fnetahtml%2Fsearch-adv.htm%2526r%3D1150%2526f%3DG%2526l%3D50%2526d%3DO179%2526s1%3D(33%2F27$.CIOR.%252Bor%252B33%2F27$.CIXR.%252Bor%252B33%2F27$.CIUX,CIDX.)%2526p%3D23%2526OS%3Dccl%2F33%2F27$%2526RS%3DCCL%2F33%2F27$&PageNum=&Rtype=&SectionNum=&idkey=33B5673FD969>
Brooke Clarke, N6GCE
George Huxtable wrote:
> 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.
>
> ================================================================
> 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.
> ================================================================
|