milli-radian
Subject: milli-radian
From: Royer, Doug (doug.royer@XXX.XXX)
Date: Wed Mar 12 2003 - 13:41:28 EST
Thanks to you guys an area of puzzelment has been cleared up for me.I often
wondered how a unit of linear measurement 0.001 was called a mil or a
thousanth.Milli-radian.It makes sense to me now.A unit of angular measure
over a short distance (relative) would appear as a straight line.Much like a
rhum line on a Mercator projection.
I have 2 mil or lensatic compasses.One is the Cammenga lensatic compass and
the other is an older Soviet Bussol compass.The Cammenga is handheld and the
Bussol is a bit larger and can be mounted on a tripod.The Bussol may be more
accurate due to the greater number of mil markings on the card face.The
Cammenga is mil marked for every 5 mils and the Bussol has markings at what
appear every 2 mils.It is also interesting in the post yesterday to discover
that Russian and US mil markings differ and I will dig deeper into this
area.I don't know the differance between the Cammenga and the US-M2 compass
but will find out today.The Bussol also has a contraption for what appears
to find elevation.It was most likely used to lay artillary positions.I can't
find any documentation on this compass but you have given me some insight on
figureing out how it works.
Ever since joining this group I haven't had a chance to read any books as I
am reading through years of your archives.What a store of knowlage and
information! I've never thought of or considered doing Lunar distance
observations but now that I have some time it sounds like a real challange
to attempt them.
Back to the Cammenga mil-compass.The bezel has a ratchet and is 120 clicks
per rev.Each click is = 53.333 mils or 3*.Each 1* is = 17.778 mils.
1 mil subtends 39.37 in. @XXX.XXX
1 min. of angle subtends 11.83 in. @XXX.XXX
1 sec. of arc subtends 0.2 in. @XXX.XXX
On to the UTM projection.UTM's have Northing and Easting coordinates.Each
section of the globe has differant East + West and North + South letters
designating the desired area to use as a prefix to the Northing and Easting
coordinates.Grids are marked as 1,000 meter boxes.Resolution is as follows.
6 digit Northing and Easting coordinates = 100 meter accuracy
8 digit coordinates = 10 meter accuracy
10 digit coordinates = 1 meter accuracy
Gentleman,I have to run and do something now so I'll finish later.
