Interesting history of its evolving definition...
Copied from the NGS Geodetic Glossary
https://www.ngs.noaa.gov/CORS-Proxy/Glossary/xml/NGS_Glossary.xml
So there's 5 of the dang things; all different? 😮
Refinements...
Interesting that when first envisioned it was linked to the dimensions of the earth. Now, like everything else, it has become more abstract; but also more precise.
thebionicman, post: 421171, member: 8136 wrote: When the kill radius of your cannon is 20 meters you can lose a little precision here and there. Kill radius minus 1 meter = error budget ..
One of my favorite instruments is a Mils T-16. I've used plenty of Mils T-2s. They don't work in kill radii.
1 meter = .5882352941176470 of a Smoot, definitely.
Larry Scott, post: 421310, member: 8766 wrote: One of my favorite instruments is a Mils T-16. I've used plenty of Mils T-2s. They don't work in kill radii.
Back in the day we would use a magnetic external scale transit called an aiming circle. You pointed it at the cannons and read the angle. When they backsighted your instrument with that angle they would be oriented the same as you. It was s quick way to lay all the guns in the same direction. My first 6 years 'surveying' were mostly that type of work. All mils and meters...
thebionicman, post: 421311, member: 8136 wrote: Back in the day we would use a magnetic external scale transit called an aiming circle. You pointed it at the cannons and read the angle. When they backsighted your instrument with that angle they would be oriented the same as you. It was s quick way to lay all the guns in the same direction. My first 6 years 'surveying' were mostly that type of work. All mils and meters...
Let there be no doubt surveying and artillery are linked. I don't know which came first: a gunner's quadrant or an alidade. And radians are natural to calculation. Mils is a rounded off radian for simplicity.
I have a military ordnance instrument that is 6350 units per circle! Took me more than few minutes to realize that.
Larry Scott, post: 421313, member: 8766 wrote: Let there be no doubt surveying and artillery are linked. I don't know which came first: a gunner's quadrant or an alidade. And radians are natural to calculation. Mils is a rounded off radian for simplicity.
I have a military ordnance instrument that is 6350 units per circle! Took me more than few minutes to realize that.
That piece is likely 6400 per circle. We loved them for the 'mil relation formula'. One mil equals 1 meter at a thousand meters. If you needed to correct 50 meters at 5 klicks it was 10 mils (one full turn on the fine adjusrment knob). It was amazing how fast you could get on target with a giod team. The ones we used were made by RCA Whirlpool and later Wild.
I was mortars. Artillery guys would put rounds in a tea cup. We dropped enough High Explosive that the cup would be obliterated regardless of position.
thebionicman, post: 421320, member: 8136 wrote: That piece is likely 6400 per circle. We loved them for the 'mil relation formula'. One mil equals 1 meter at a thousand meters. If you needed to correct 50 meters at 5 klicks it was 10 mils (one full turn on the fine adjusrment knob). It was amazing how fast you could get on target with a giod team. The ones we used were made by RCA Whirlpool and later Wild.
I was mortars. Artillery guys would put rounds in a tea cup. We dropped enough High Explosive that the cup would be obliterated regardless of position.
No it's not likely 6400, it has a scale. (I misspoke, it's 6300 to the circle.) The scale only has 6300 units on its circle. Right angle is 1575 units. Pre-NATO, Dutch or Danish tried their own standard, and 6300 is closer to milli-rads. I believe the unit is called Strecht (sp?). I assumed it was Mils for about 5 minutes. The high number on the circle is 6299. It's a good example of how arbitrary angle units can be. I really prefer Mils T2 for control work.
http://forums.gunboards.com/archive/index.php/t-45764.html
This is not a high end instrument, but it was their unit of choice; until NATO.
Larry Scott, post: 421329, member: 8766 wrote: No it's not likely 6400, it has a scale. (I misspoke, it's 6300 to the circle.) The scale only has 6300 units on its circle. Right angle is 1575 units. Pre-NATO, Dutch or Danish tried their own standard, and 6300 is closer to milli-rads. I believe the unit is called Strecht (sp?). I assumed it was Mils for about 5 minutes. The high number on the circle is 6299. It's a good example of how arbitrary angle units can be. I really prefer Mils T2 for control work.
http://forums.gunboards.com/archive/index.php/t-45764.html
This is not a high end instrument, but it was their unit of choice; until NATO.
Very cool. Notice the double scales? One measures azimuth and the other is for deflection. That instrument would allow you to orient all cannons in a section the same direction with no control.
Sorry for the hijack folks but this is pretty cool stuff..
thebionicman, post: 421346, member: 8136 wrote: Very cool. Notice the double scales? One measures azimuth and the other is for deflection. That instrument would allow you to orient all cannons in a section the same direction with no control.
Sorry for the hijack folks but this is pretty cool stuff..
The two scales are just for left and right hand angles. It has upper and lower motions, it's a repeater so you can wrap an angle. It's a transit. It'll fit inside a quart size oil can. The funny thing is that it has 5/8-11 tripod thread.
And it's an eBay find. At 6300 units it's a fun find.
Larry Scott, post: 421383, member: 8766 wrote: The two scales are just for left and right hand angles. It has upper and lower motions, it's a repeater so you can wrap an angle. It's a transit. It'll fit inside a quart size oil can. The funny thing is that it has 5/8-11 tripod thread.
And it's an eBay find. At 6300 units it's a fun find.
I was just describing the way it was used (in fire direction). Having complimentary scales opens doors for unusual techniques. Its actually a practical way to transfer baselines where direction is critical.
Thanj you for sharing the pics and info.
