NavList:
A Community Devoted to the Preservation and Practice of Celestial Navigation and Other Methods of Traditional Wayfinding
Re: Comments on the units
From: Lu Abel
Date: 2006 Apr 8, 08:29 -0700
From: Lu Abel
Date: 2006 Apr 8, 08:29 -0700
I'm not sure I'd agree, Alexandre. 64000 "mils" is real close to 1000 * 2 * Pi. That would make range vs height calculations very simple, as I'm sure you already know. Lu Abel PS - for those who are scratching their heads over some of this discussion, the sine and tangent of small angles are nearly identical and the same as the angle itself measured in radians (if you've forgotten, there are 2*Pi radians in a circle). In this example of US Army "mils," something that was 1000 yards away and subtended 2 mils in a range-finding scope would be 2 yards (or six feet) in size. Or, since the Army has gone metric, something one "click" (Army slang for a kilometer) away would be 2 meters high. Alexandre E Eremenko wrote: > Interesting! > So the American artillerists sacrifice the ease of calculation > to higher precision. > A > > Alex Eremenko > Department of Mathematics > Purdue University > West Lafayette IN 47907-2067 > > Please do not send me attachments encoded in a secret proprietary format > such that MS Word or Power Point; I am unable to read them. Please use > instead a publicly available format such as PDF or plain text (ASCII). > For more information, see > http://www.gnu.org/philosophy/no-word-attachments.html > > On Fri, 7 Apr 2006, Royer, Doug wrote: > > >>Alex wrote: >>And the compass ("bussole" in Soviet artillery, >>but compass in the Soviet Navy) >>was divided into 60 parts, correct? >> >>Do US and British Armies use degrees? >>A. >> >>On Fri, 7 Apr 2006, jean-philippe planas wrote: >> >> >>>The French artillery (and infantry) >>>uses division called "thousandth" (milli�me") as well. "One Thousandth" >>>is the angle of an object one meter high seen from a 1000m (1 km >>>distance) with the same conclusions as Alex. >>> JPP >> >>In the US military (land forces at least) a recruit is trained for land nav >>using compasses/optics that are graduated in degrees and mils. >>In the US equipment there are 6400 mils to 360 degrees. And on long range >>optics (rifle scopes, arty optics etc) there are markings on the horizontal >>and vertical stadia for range finding. These markings (round dots) are 1 mil >>in diam. Because 1 mil subtends a certain area at certain ranges these >>optics give good results in range finding. >>I had a Russian (Soviet actually) compass a few years ago. It, as you >>stated, was marked in 6,000 units instead of the 6,400 units I was used to >>using. It was confusing as I always had to think about the difference when >>using it instead of just using the equipment. I got rid of the Soviet >>compass. Not because of inferior quality of the compass but I am comfortable >>using 6400 mils to a circle. >> > > >