The most widespread in the past tense was the Adrianova compass. It consists of a round box in which the magnetic needle rotates on the tip of the needle. A ring (limb) with divisions in degree degree and in thousandths (tens of thousandths) is placed in his box. In addition, instead of 90, 180, 270 and 360 degrees, strokes are plotted on the limb and marked with the initial letters of the horizon: “C” is north, “B” is east, “U” is south, “3” is west.
How Adrianov’s compass is arranged, how to use it to navigate the terrain, determine the sides of the horizon, the azimuth of the direction to the object, the desired direction for movement.
The divisions in degrees on the limb of the Adrianov compass are plotted after three degrees and increase clockwise, and in thousandths (50 thousandths – 0-50) – in the opposite direction. The Adrianov’s compass has a glass rotating lid on top with a slot and a front sight for aiming (sighting) a reference point in determining the direction of movement.
Pointers are strengthened to count degrees against the front sight and slots. The non-operational compass needle is locked by the brake. Its northern end, indicators for reading angles and strokes corresponding to the cardinal points (C, B, S, 3) are covered with a luminous composition, which ensures their good visibility even at night.
In a freely suspended state, the magnetic needle with its ends will always be directed north and south. But this is approximate. In fact, it is located not in the direction of the true (geographical) meridian, but in the direction of the so-called magnetic meridian. We call this angle the declination of the magnetic needle. It is different for each locality..
It can be eastern (with a + sign) and western (with a – sign). Its magnitude for most of Europe and Asia does not exceed 5-7 degrees, with the exception of areas of magnetic anomalies. Therefore, we will assume that the magnetic meridian practically coincides with the true one, and the northern end of the magnetic needle always points to the north.
Determining the sides of the horizon using the Adrianov compass.
With the help of Adrianov’s compass, you can easily determine the sides of the horizon. To do this, release the brake arrows and set the compass horizontally. So that the arrow does not touch the end of the glass of the lid or the bottom of the box. Then turn the Adrianov’s compass so that the northern end of the magnetic needle is opposite the letter “C”, then the letters “B”, “3”, “U” will indicate directions to the east, west, south.
And in any of these directions, you can choose a landmark on the terrain that we will use in future orientation on the terrain. So, for example, if we need to move east, then we select a remote landmark located in the east (by compass), and move to it, that is, go east.
Determining the azimuth of a direction to a local object using the Adrianov compass.
But more often you have to make movements not in the directions of the sides of the horizon, but in other directions. How to use a compass in this case? To determine the azimuth of the direction to any local object, you need to face it, release the brake of the magnetic needle and orient the Adrianov’s compass, that is, combine the end of the arrow with zero division of the degree ring of the compass.
Then, holding Adrianov’s compass at eye level and not disrupting the compass’s orientation, carefully turn the compass lid so that the notch on it is facing us, and the front sight is exactly in the direction of the reference. This position of the lid can be given if you look through the slot and the front sight at an observing object. In this case, you must always make sure that the northern end of the arrow coincides with zero division of the scale.
This technique is well performed if the Adrianov’s compass is not held at eye level when sighted, but 10-15 cm lower. Sighting is carried out according to the position of a pencil or any stick installed in the slot and front sight, and mentally continuing this line, direct it to the selected landmark.
It’s good to do it together. When one accurately monitors the orientation of the compass, and the second determines the direction of the cover by the position of the cover. After that, the magnetic azimuth is counted against the pointer of the front sight. So, for example, in the figure below, the magnetic azimuth to a separate tree is 240 degrees.
Determining the desired direction for movement using the Adrianov compass.
Using the Adrianov compass, you can also solve the inverse problem, that is, for a given magnetic azimuth, you need to find the direction for movement on the terrain. Such problems often have to be solved in practice when moving along azimuths. In this case, in order to find the desired direction on the ground, it is necessary to set the fly pointer to the specified magnetic azimuth and release the brake of the magnetic needle.
Then, setting the Adrianov’s compass in a horizontal position, orient it. Without knocking down the compass’s orientation, you need to look at the visibility through the slot and the front sight and notice a guideline on this line. The direction from the point of its location to this landmark will correspond to a given magnetic azimuth.
If the magnetic azimuth is set in the forest, where it is impossible to choose a long-range landmark, then they remember some tree located as far as possible in this direction, and move towards it. From it they go to the next, etc. Until they come out of the forest or come to the indicated landmark.
Based on the book “Map and Compass My Friends”.