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Re: Understanding Milliradians
Posted: Thu Feb 11, 2016 10:02 am
by George G
George G wrote:I think that an important step has been left out, and once that step is understood then much confusion goes away. As shown, mathematically a radian is just under 57.3 degrees, and so if you divide that by 1000 to make it into milliradians you get about 6,283 in a full circle.
6,283 is not a convenient number, and so instead an approximation has been invented, called rads and millirads, (note the rads bit, not radians) where it has been decreed there are 6,400 rads in a circle, which makes for easier use. (Thus 3,200 in half a circle. 1,600 in a right angle.)
In the second paragraph delete 6,400
rads in a circle, insert 6,400
millirads in a circle.
Sorry about the error
Re: Understanding Milliradians
Posted: Thu Feb 11, 2016 12:01 pm
by Gazoo
I'm sorry where did the bang bang forum go, whats this about Ed Milliband radiating something. There where numbers and little shapes that look like letters but aren't and then people talking about pie BUT THERE IS NONE!!!!
Is there a help line number I can phone to be patronised by a spotty 17 yr old?
where have all the luddites gone, I own a hammer you know and a spear and jackson spade with the number 7 shaft.
Re: Understanding Milliradians
Posted: Thu Feb 11, 2016 12:33 pm
by Polchraine
Did you know you can get compasses graduated in Rad/milliRad - well the outer ring is actually in deciRads (0 - 64)
http://silva.se/product/compasses/compa ... 400-green/
Re: Understanding Milliradians
Posted: Thu Feb 11, 2016 1:53 pm
by George G
Yeah,
I once borrowed a Silva compass from the army and found it was in millirads.
WTF?
Re: Understanding Milliradians
Posted: Thu Feb 11, 2016 1:57 pm
by snayperskaya
Chuck wrote:It is from where I'm sitting......
Mil Dots, milliradians...somehow a wee bit left/right / up /down seems easier ...
I agree.....thank God for BDC turrets as well!.
Re: Understanding Milliradians
Posted: Thu Feb 11, 2016 2:05 pm
by Polchraine
George G wrote:Yeah,
I once borrowed a Silva compass from the army and found it was in millirads.
WTF?
They can be quite useful once you understand them ... the ring tends to be marked 0 to 64
So, N is 0, South 32, East 16 and West 48
In between those, NE 8, NNE 4 and NbE 2
If using degrees those last three would be: 45, 22.5 and 11.25 - which is easier to work with?
Re: Understanding Milliradians
Posted: Thu Feb 11, 2016 3:35 pm
by channel12
George G wrote:George G wrote:I think that an important step has been left out, and once that step is understood then much confusion goes away. As shown, mathematically a radian is just under 57.3 degrees, and so if you divide that by 1000 to make it into milliradians you get about 6,283 in a full circle.
6,283 is not a convenient number, and so instead an approximation has been invented, called rads and millirads, (note the rads bit, not radians) where it has been decreed there are 6,400 rads in a circle, which makes for easier use. (Thus 3,200 in half a circle. 1,600 in a right angle.)
In the second paragraph delete 6,400
rads in a circle, insert 6,400
millirads in a circle.
Sorry about the error
Sorry but you made another error, the mil and milliradian are not actual the same unit of angular measurements.
There are as you say 6,283 milliradians (milrads) in a circle, however the military rounded that up to make 6,400 mils in a circle. Therefore we shouldn't really say millirad if we mean mil because although mathematical similar they are derived from different sources. For the distances we shoot at it doesn't matter but at astronomical distances it does.
Re: Understanding Milliradians
Posted: Thu Feb 11, 2016 6:19 pm
by George G
channel12 wrote:George G wrote:George G wrote:I think that an important step has been left out, and once that step is understood then much confusion goes away. As shown, mathematically a radian is just under 57.3 degrees, and so if you divide that by 1000 to make it into milliradians you get about 6,283 in a full circle.
6,283 is not a convenient number, and so instead an approximation has been invented, called rads and millirads, (note the rads bit, not radians) where it has been decreed there are 6,400 rads in a circle, which makes for easier use. (Thus 3,200 in half a circle. 1,600 in a right angle.)
In the second paragraph delete 6,400
rads in a circle, insert 6,400
millirads in a circle.
Sorry about the error
Sorry but you made another error, the mil and milliradian are not actual the same unit of angular measurements.
There are as you say 6,283 milliradians (milrads) in a circle, however the military rounded that up to make 6,400 mils in a circle. Therefore we shouldn't really say millirad if we mean mil because although mathematical similar they are derived from different sources. For the distances we shoot at it doesn't matter but at astronomical distances it does.
Exactly!
Re: Understanding Milliradians
Posted: Thu Feb 11, 2016 8:44 pm
by channel12
The Swedish military originally went for 6300 mils in a circle, the Russians use 6000 mils in circle, NATO decided on 6400 mils.
Re: Understanding Milliradians
Posted: Fri Feb 12, 2016 9:04 am
by George G
Polchraine wrote:George G wrote:Yeah,
I once borrowed a Silva compass from the army and found it was in millirads.
WTF?
They can be quite useful once you understand them ... the ring tends to be marked 0 to 64
So, N is 0, South 32, East 16 and West 48
In between those, NE 8, NNE 4 and NbE 2
If using degrees those last three would be: 45, 22.5 and 11.25 - which is easier to work with?
The last three have been in use since time immemorial for navigation. Eleven and one quarter degrees is one point of the compass, twenty two and a half degrees is two points etc. The points of the compass are still widely used and understood. Ask any yachtsman.