OK...Artillery 101...Here are some simple explanations
An artillery weapon is surveyed into position, ie. the tube is suveyed pointing in a direction you want to fire. When the survey is complete and without moving the tube, the sight is set to a reference setting. For this type of site it would be 2800 mils (6400 mils in a circle). Now with the refernce setting and the tube lined up on the direction to fire reference points are put out so that when you sight through the pantel and you could line up on them.
Reference Point
The earliest form of aiming point was a pair of aiming posts for each gun, almost in line with one another when viewed through the gun's sight, and placed about 50 meters from the gun. There were at least two ways of using these but the simplest is to aim the sight mid-way between them.
Before the First World War the French introduced the collimateur. During that war the British introduced their first parallescope which was a horizontal mirror placed a few feet from the gun, the layer aimed his sight at its reflection. In the 1950s the parallescope was replaced by the prism parallescope that was more robust and easily positioned. In the 1970s the US introduced a modern version of the French device and called it a collimator. In the same period infra-red beacons had some very limited use.
In some special circumstances, such as when only one round or salvo was going to be fired (eg by nuclear artillery or a multiple rocket launcher), a director or aiming circle about a 100 meters away could be used as an aiming point
The aiming posts are those poles that look like candy cane poles. In WWII they were red & white (later...VN, green and black)
Now with a reference, you could move the tube or the site but if you wanted to get back to the surveyed azimuth of fire, set the site using the lower knob to 2800 and traverse the tube until you center your reference points in the retical of the pantel. The tube is back.
Ballistic calculations to any other target which require you to move left or right of the azimuth of fire calculate the difference in mils. That value is set using the lower knob on the site and then looking through the pantel you traverse the tube until you center it on the reference point. It is now pointing at that target.
Phew...I know that was a lot and I hope it was understandable???
Lastly, there is no reference point on the tube, the pantel is aligned and moves with the tube.
Next...Top knob...The top know allows you to see your reference point in the center of the retical if it is up a hill or down on the ground. Essentially it allows you to make up the difference in elevation from the weapon to the reference point.
It is not used for elevation in direct fire. On the other side of the weapon is the elbow telescope. This is used for sighting elevation and the weapon is elevated from that side.
Do they need a compass...No, once the tube is suveyed into position and the tube aligned on a azimuth of fire, and you have reference points out, as I said above, the traverse to a target is left or right of the surveyed azimuth of fire. This would be calculated and sent to the gun. They would set off the "deflection" on the site and the traverse the tube to the aiming point.
The gunner operates the pantel telescope and traverses the gun. The asst. gunner elevates the tube.
The entire site is about 12 - 15 inches tall. The optics are pointing in about the right direction. From the back of a weapon the site is mounted on the left side. The eyepiece would stick out to the left. Aiming points are to the left front side of the weapon, so at times it could be almost looking over the eyepiece.
OK, I know you are compleatly confused. Hopefully this helps a little.
If no one else has any questions, if you want more information you could either PM me, (I hope the other in this forum don.t mind the long winded explanation), also look on the internet. Use the following searches
- Panoramic Telescope
- Aiming Posts
- Collimater
- Artillery Survey
- FM-6-30
- FM-6-40
I'm here behind the breech block if you need more!!
Rounds Complete!!