How to determine the azimuth of the starting point. Determination of magnetic azimuths

Azimuth measurement is one of the main tasks in orientation. Without solving this problem, it is unlikely that it will be possible to maintain the correct direction of movement in the absence of noticeable landmarks, just as it will not be possible to solve a number of other problems related to orientation.

Typically, azimuth is determined using a protractor or compass. We told you how to do this in. What to do if neither one nor the other tool is at hand? Is it possible to determine azimuth without a compass using a map? Does it even make sense to determine the azimuth and, if so, how can this be done?

Is it necessary to determine azimuth if there is no compass?

Necessary, but not always.

If a person has a map of the area, and the area itself is rich in clearly visible landmarks, then in most cases it is possible to do without measuring azimuth at all. In such cases, it is most convenient to move along the roads and paths marked on the map, and if you move directly, then to a clearly visible object marked on the map.

Azimuth is required if a person cannot determine the required direction of his movement at all.

However, in some situations it will be very difficult to do without azimuth. Let's consider several such situations:

• There is a map, but there are few landmarks on it, and they are difficult to trace from the terrain, for example, in dense forest conditions. In this case, most likely, in order to achieve the goal, it will be necessary to move along azimuths, having previously measured them.
• There is no map, but there is an emergency azimuth value. In this case, if a person gets lost, he will have to look for the direction of movement according to the emergency azimuth. We talked in detail about emergency azimuth here.
• There is no map and the value of the emergency azimuth is not known. In this case, the ability to find the direction of movement in azimuth will help you move in a straight line rather than zigzag.

By the way, some people believe that in the absence of a map, determining the cardinal directions and azimuth is an absolutely useless task. But, as we see, this is not so.

How to find azimuth without a compass and protractor

In order to measure azimuth, you need to remember that azimuth is essentially an angle measured clockwise relative to the north direction. This means that all the methods that we will analyze here come down to determining the cardinal points and angles without special tools.

Having determined the direction to the north, for example, according to the Sun, it is possible to calculate the azimuth to the desired object with a certain accuracy.

We talked about how to find the direction to north, south, east and west without a compass and navigator here and here. Now the task is to know the direction to the north and determine the angle between it and the desired direction of movement.

The easiest way to do this is with a protractor. In this case, the protractor is placed so that its base coincides with the direction to the north, and the central point coincides with the point from which the azimuth will be determined. Some thin long object (for example, a stick or a match) is placed on the protractor so that its top lies at the central point of the protractor, and the second top points to the direction chosen for movement or to the object to which the azimuth is determined. The angle at which the stick on the protractor points will be the azimuth.

The inverse problem is solved similarly: if the azimuth is known, the protractor is placed with its base in the direction of the north, the match is placed with one end in the center, the other at an angle equal to the azimuth. The second end in this case indicates the direction corresponding to the azimuth.

In fact, now the task comes down to finding a protractor: after all, this item does not often end up in a tourist’s backpack. However, this is not a problem: a protractor can be quickly made from scrap materials.

Method No. 1. Homemade paper protractor.

Such a protractor can be made within one minute and does not require special knowledge and skills from a person. In order to make it, you need:

1. A sheet of paper does not have to be folded in half in an even shape - it turns out to be an angle of 180°.
2. Bend the resulting figure perpendicular to the previous fold - an angle of 90° is obtained.
3. Bend the folded sheet, dividing the resulting angle (90°) in half - an angle of 45° is obtained.
4. Cut off or tear off the very tip of the sharp corner of the resulting paper figure to create a hole.
5. Expand the sheet.

The result is a kind of paper protractor that has a hole in the center. This hole is applied to the point from which it will be necessary to measure the azimuth. “Rays” - naminas - extend in different directions from the hole - the angular distance between them is 45°. The video shows how to do this:

Method number 2. Homemade protractor made from paper and a wristwatch.

A watch with a round dial will help you draw a sheet of paper into 15° sectors. For this:

1. A sheet of paper is folded in a manner similar to the previous method until a cross of two perpendicular namins is formed on it.
2. The clock is placed on the sheet with the dial facing up.
3. The clock is shifted and rotated so that the vertical line on the paper intersects the numbers “6” and “12”, and the horizontal line crosses the numbers “3” and “9” on the clock dial. Thus, we can say that the intersection of the namins coincides with the center of the watch dial.
4. A dot is placed on a piece of paper next to each number on the watch dial.
5. The clock is put aside, and all the points on the paper are connected by segments, forming a 12-gon.
6. A dot is placed in the middle of each segment.
7. From the point of intersection of the namins towards each of the marked points (to each corner of the polygon and the point dividing the segments in half), rays are drawn using a ruler. It turns out 24 rays.
8. A small hole is made in the center of the resulting drawing for ease of use of a homemade protractor.

The resulting protractor differs from the previous one in having a smaller division value (15°), which means it can be used to measure azimuths more accurately.

Such protractors can be quickly made, but, unfortunately, azimuths other than multiples of 45° and 15° can only be measured by eye, which means you cannot expect great accuracy from such measurements.

Obviously, if you make marks on such protractors approximately in the middle between the marks, similarly cut the distances between them in two, and then repeat this again and again, you can get angles of 22.5°, 11.5°, 7.5°, 3. 75° and so on. For terrain orientation conditions this will be sufficient.

If the accuracy of azimuth determination is not critical, then these methods are quite suitable for use. In cases where it is necessary to focus on accuracy, they can be clarified using the method that will be discussed further.

Method No. 3. Clarifying.

This method is in addition to the first two. With its help, you can clarify the angle if it lies outside the division scale of a homemade protractor.

This method is based on the knowledge that at a distance of 57 centimeters from the observer, a distance of 1 centimeter has an angular length corresponding to approximately 1°.

Thus, in order to clarify the azimuth, you need:

1. From the center of the protractor, draw a segment 57 centimeters long through the division of the protractor, as close as possible to the desired azimuth.
2. Lay a similar segment along the desired azimuth, that is, from the center of the protractor to the landmark to which the azimuth needs to be measured.
3. Measure the distance between the ends of the resulting segments.
4. Convert the resulting length to degrees with the expectation that 1 centimeter is equal to 1 degree.
5. Calculate the azimuth by subtracting or adding the resulting value to the value of the protractor division relative to which the azimuth was specified. If the desired direction is shifted counterclockwise from the mark, then the resulting value is subtracted from the value of the mark; if it is shifted clockwise, then it is added.

In order to obtain more or less accurate azimuth values, for this method it is not necessary to draw a sheet of paper using a clock: it is quite enough to simply bend the sheet as described in the first method.

In general, when choosing a method for measuring azimuth without the help of special navigation tools, you need to pay attention to what specific orientation method is used.

For example, you should not chase headlong for great accuracy if you have to cross the terrain during daylight hours, since solar orientation is in most cases a very approximate method, which means that small errors obtained when measuring azimuths can be neglected . If movement along the route is planned for the night, and the method of determining the cardinal directions by the North Star was chosen as the orientation method, then, if necessary, you can try to make the calculations more carefully.

In any case, it is better to avoid situations where you have to navigate without a compass. To prevent such situations, you need to take two compasses on a hike - a main one and a spare one - and also make sure that each participant in the hike has their own navigation device.

The essence of movement along azimuths is to maintain on the ground the directions specified by magnetic azimuths and the distances determined from the map.

Magnetic azimuth and its definition. When determining the direction to a local object, magnetic azimuth is usually used.

Magnetic azimuth is called a horizontal angle measured clockwise from the north direction of the magnetic meridian to the direction towards the object. It has values ​​from 0 to 360 degrees.

To determine the magnetic azimuth to a local object using a compass, you need to face this object and orient the compass. Then, holding the compass in an oriented position, install the sighting device so that the sighting line of the front sight slot coincides with the direction of the local object. In this position, the reading on the dial opposite the pointer at the front sight will show the value of the magnetic (direct) azimuth (direction) to the local object (Fig. 78).

Rice. 78. Magnetic azimuths: to a deciduous tree - 56°; on a factory pipe - 137°; to the windmill - 244°; on spruce - 323°

Back azimuth- this is the direction from a local object to a standing point. It differs from direct azimuth by 180°. To determine it, you need to add 180° to the direct azimuth if it is less than 180°, or subtract 180° if it is more than 180°.

To determine the direction on the ground based on a given magnetic azimuth, it is necessary to set the front sight pointer to a reading equal to the value of the given magnetic azimuth and orient the compass. Then, holding the compass in an oriented position, notice a distant object (landmark) on the ground along the sighting line. The direction towards this object (landmark) will be the one you are looking for.

When working with a compass, you need to hold it 10 cm below eye level in your left hand, with your elbow firmly pressed to your side for stability.

Movement in azimuths. To move along azimuths, it is necessary to know the magnetic azimuths from each point on the route and the distance between points of movement in pairs of steps (for a person of average height, a pair of steps is taken as 1.5 m). When driving a car, the distance is measured using the speedometer. This data is prepared by the commander and drawn up in the form of a route diagram.

Rice. 79. Scheme of the route in azimuths (latitude - a couple of steps)

When moving, they move from one point to another, maintaining the direction of landmarks and counting pairs of steps. At the starting and turning points, the direction of movement is found using a given azimuth using a compass. In this direction, either a more distant landmark (auxiliary) or a landmark located closer to the turning point of the route (intermediate) is selected and remembered. If the turning point is not visible from an intermediate landmark, then the next landmark is determined.

In open areas without landmarks, the direction of movement is maintained along the target. At the starting point, the compass is used to determine the direction of movement to the next point. Moving in this direction, they place some signs at some distance from one another. Periodically looking back at them, make sure that the direction of further movement coincides with a straight line mentally drawn through the signs left behind (traces of one’s own movement). For control, the direction of movement is periodically checked using the reverse azimuth and celestial bodies. Reached landmarks are constantly compared with given landmarks, and if a map (scheme) is available, the terrain and route are compared with it. If it is necessary to return back along the same path, then they use the previous route diagram, for which they first convert forward azimuths to reverse ones.

At night, silhouettes of local objects, points glowing in the distance, and bright stars are used as intermediate (auxiliary) landmarks. If this is not possible, then the compass with a freely lowered arrow is kept in front of you in an oriented position at all times, and the straight line passing through the slot and the front sight is taken as the direction of movement.

To avoid an obstacle (if visibility is available), proceed as follows: notice a landmark in the direction of movement on the opposite side of the obstacle, determine the distance to it and add this value to the length of the path traveled; bypass the obstacle and continue moving from the chosen landmark, having previously determined the direction of the interrupted path using the compass.

1. What data is needed to move along azimuths?
2. Determine your step size and convert the distance of 100 m into pairs of steps.
3. Determine the azimuths of possible directions of movement from home to the educational institution.
4. Define back azimuths for azimuths 70°, 120°, 170°, 285°.

Determination of the sides of the horizon, magnetic azimuths, horizontal angles and compass direction

Determining directions to the sides of the horizon using a compass

Using a compass, you can most conveniently and quickly determine north, south, west and east (Fig. 1). To do this, you need to give the compass a horizontal position, release the arrow from the clamp, and let it calm down. Then the arrow-shaped end of the arrow will point north.

Rice. 1 Determining the sides of the horizon using a compass

To determine the accuracy of the deviation of the direction of movement from the direction to the north or to determine the positions of terrain points in relation to the direction to the north and counting them, divisions are marked on the compass, of which the lower divisions are indicated in degree measures (the value of the division is 3 °), and the upper divisions of the protractor in tens of thousands.

Degrees are counted clockwise from 0 to 360°, and protractor divisions are counted counterclockwise from 0 to 600°. The zero division is located at the letter “C” (north), and there is also a triangle glowing in the dark, which replaces the letter “C” in some compasses.

Under the letters “B” (east), “Y” (south), “3” (west) there are luminous dots. On the movable cover of the compass there is a sighting device (sight and front sight), against which luminous indicators are mounted, which serve to indicate the direction of movement at night. The most common compass in the army is the Andrianov system and the artillery compass.

When working with a compass, you should always remember that strong electromagnetic fields or nearby metal objects will deflect the needle from its correct position. Therefore, when determining compass directions, it is necessary to move 40-50 m away from power lines, railroad tracks, military vehicles and other large metal objects.

Determining directions to the sides of the horizon using a compass is performed as follows. The sighting device's front sight is placed on the zero scale division, and the compass is placed in a horizontal position. Then the brake of the magnetic needle is released and the compass is turned so that its northern end coincides with the zero reading. After this, without changing the position of the compass, a distant landmark is noticed by sighting through the rear sight and front sight, which is used to indicate the direction to the north.

Rice. 2 Relative position of the sides of the horizon Directions to the sides of the horizon are interconnected (Fig. 2), and if at least one of them is known, the rest can be determined

The opposite direction to north will be south, to the right is east, and to the left is west.

Determination of magnetic azimuth by compass

Magnetic direction azimuth determined using a compass (Fig. 3). At the same time, the brake of the magnetic needle is released and the compass is turned in a horizontal plane until the northern end of the needle is positioned against the zero division of the scale.

Then, without changing the position of the compass, install the sighting device so that the line of sight through the rear sight and front sight coincides with the direction of the object. The scale reading against the front sight corresponds to the value of the determined magnetic azimuth of the direction to the local object.

The direction azimuth from the standing point to a local object is called direct magnetic azimuth. In some cases, for example, to find a return path, they use reverse magnetic azimuth, which differs from the straight line by 180°. To determine the reverse azimuth, you need to add 180° to the forward azimuth if it is less than 180°, or subtract 180° if it is greater than 180°.

Rice. 3 Determination of the magnetic azimuth direction to a separate tree

Determining horizontal angles using a compass

First, the front sight of the compass sighting device is set to zero on the scale. Then, by turning the compass in a horizontal plane, align the line of sight through the rear sight and front sight with the direction to the left object (landmark).

After this, without changing the position of the compass, the sighting device is moved to the direction of the right object and a reading is taken on the scale, which will correspond to the value of the measured angle in degrees.

When measuring an angle in thousandths The line of sight is first aligned with the direction towards the right object (landmark), since the count of thousandths increases counterclockwise.

With the sighting device until the line coincides with a distant and visible object, structure or tree. Take a count azimuth but on this subject. Count from the zero value of the scale clockwise to the number on the scale located opposite the pointer of the viewfinder.

Correctly align the line of sight with the line of direction to the selected object by moving your gaze several times from the line of sight to the object. Do not raise the compass to your eyes, this will easily impair the accuracy of the determination. azimuth A. Use special compasses, such as Andrianov systems, to obtain greater magnetic accuracy azimuth A.

If you need to move from the selected object in the opposite direction, define the reverse magnetic azimuth. To do this, add 180 to the straight line azimuth y if its digital value is less than 180 degrees or subtract 180 degrees if its digital value is 180 degrees.

To correctly determine the direction using the previously obtained magnetic azimuth y, rotating the sight ring, align its pointer with a number on the scale equal to the previously determined magnetic value azimuth A. Then remove the brake and rotate the compass body until the northern edge of the needle coincides with the zero mark of the scale. The line of sight will determine the desired direction. For further movement, mark a clearly visible free-standing landmark along the line of sight.

Everyone at least once in their life has had to walk in the forest and think about what to do if they get lost. You can navigate the terrain in different ways, there are many ways, the most common are a compass and clearly visible objects in the surrounding area.

Instructions

Azimuth- this is the angle that is formed between the direction of any viewed object of the terrain and the direction. Azimuth s are calculated clockwise and their magnitude is from 0 to 360 degrees. To determine the magnetic azimuth of an object, take a compass and face the indicated object.

Now place a match on the glass lid of the compass so that one end of it is through the center of the compass, and the other is directed at the selected area object. Look through the glass at the bottom of the compass and read the number that is located under the outer end of the match. This figure shows the value.

Azimuth can also be determined by . To do this, place a compass on the side edge of the map, turn the card so that its side edge coincides with the direction of the magnetic compass needle to the north. The top edge of the map should be above the letter C. Then find the point from which the movement will begin, connect it with a straight line to the object to which you need to arrive. Then move the compass so that its center is at the starting point. The line on the map will be located opposite a certain number on, which will show the azimuth value.

Azimuth, calculated from the standing point on the terrain, is called direct magnetic azimuth. To find the way back, they often use the concept of reverse azimuth, which is 180 degrees different from the direct one. To determine the reverse azimuth, you need to add 180 degrees to the forward azimuth if it is less than 180 degrees; or subtract if it is greater than 180 degrees.

Sources:

• Azimuths and movement along azimuths

Magnetic azimuths measured from the direction of the magnetic meridian, which is indicated by the direction of the magnetic compass needle. A conditional azimuth is called when a conditional meridian is taken to calculate it.

Instructions

If you know the declination angle for a certain point at a certain epoch, you can determine with a certain accuracy the true magnetic azimuth and, conversely, the true magnetic azimuth. All meridians converge at the same point - . The angle between two is the name of the angle of approach of the meridians. If you intersect several meridians with a straight line, at the points of their intersection azimuths, differing from each other by this very angle of convergence of the meridians. Its magnitude of two points of one straight line will depend on its length, direction, as well as the latitude of the place. The azimuth, which is measured at the starting point of the line, is called direct. The reverse azimuth (a2) is equal to the forward azimuth (a1) plus or minus 180 degrees, as well as plus the angle of approach of the meridians (t). It turns out: a2=a1±180°+t.

For a line of 15 km in mid-latitudes, the angle of convergence of the meridians is approximately 10’ in everyday practice; as a rule, such a small angle is neglected, considering that the direct and reverse azimuths differ from each other by 180o (a2=a1±180o). This is accepted at a lower level in cases with small surfaces.

For large distances, as well as high-precision measurements, calculations are made according to all the rules of higher geodesy, taking into account the angle of approach of the meridians and the spherical kurtosis, expressed in centimeters. The formula in such cases is as follows: a2=a1±180°+t-e, ​​where t is the approach angle, which is calculated using special formulas, e is the spherical kurtosis, which is also calculated using a special formula.

Video on the topic

The word "azimuth" comes from the Arabic "as-sumut", which means "path", "direction". The most commonly used phrases with the word azimuth are the azimuth of a celestial body and the azimuth of an earthly object. Azimuth is the angle between the meridian passing through the observer’s location and the direction to a specific object. In practice, this is the angle between the local object, measured north clockwise in degrees, and the direction north.

At school they told me how to determine azimuth using a compass. I remember this, but never in my life have I been able to put it into practice. I even have a compass at home, everything is waiting in the wings.

Determination of azimuth by compass

Why do you need to look for azimuth? To quickly find your way around. To do this you will need a map and compass. In ancient times, people were able to determine it by the stars, the Sun and improvised objects. Now everything has changed, although these methods can still help in our time.

Let's say I'm now in a mountainous area. I have a compass in one hand and a local map in the other. Here's what I do next.

1. I determine my location and the correct course I will take. To begin with, I will choose a reference point for myself. This could be a large tree or other object. I take a compass and a map.
2. The compass has a special mechanism that keeps the needle on the brake. It is magnetized and always points north. First, I make sure that there is nothing nearby made or constructed of metal. There is a possibility that the arrow will point in the wrong direction. Now you can release the arrow from the brake.
3. I place the device on the map so that the compass needle coincides with the mark on the map that points north.
4. Now I determine the azimuth. The azimuth will be the angle between the north arrow and the landmark.
5. This is how I determine the azimuth, which will help me find the right path on the ground.

DIY compass

Not everyone has a compass at hand. Therefore, you can do it yourself. Of course, a professional device will show more accurate results, and it is also equipped with additional features, but it is not always possible to use this.

How to make a compass at home.

1. Take a small piece of polystyrene foam or any material that does not sink in water and a needle.
2. Hold one side of the needle near the magnet for a few minutes.
3. Demagnetize the other side using fire.
4. Pierce the foam with a needle.
5. Pour water into a non-metallic container and place an improvised magnetic needle in it.