Determination of time by sundial. How to tell time by the sun

For many people it is vital to know exact time. If suddenly you happen to find yourself in an environment where survival and your own safety are at stake, the ability to tell the time (if you do not have a watch) will be extremely useful.

Agree, it is difficult to guess the exact time without a clock, but we will try not to guess it, but to determine it by the sun, moon and stars.

I. Determination of time by the sun

1. Determine the position of the sun:

If you are in the northern hemisphere, face south; if you are in the southern hemisphere, face north (If you do not have a compass with you, use the following methods to determine the parts of the world). Look at the equator, the line between heaven and earth where the sun rises and sets. As you know, the sun rises in the East (which will be on the left if you are facing the South, and on the right if you turn your gaze to the North) and sets in the West.

If the sun in the sky is exactly in the center, then it is noon - 12:00. But there are a number of deviations here, which depend on summer time and your location relative to the time zone.

If the sun is not exactly centered in the sky, you have to do some calculations. In the morning the sun is in the eastern part of the sky, at noon it is in the western part. Mentally divide the sky into equal parts, then you can find out the approximate time.

2. Calculate the number of hours between sunrise and sunset:

This amount depends on the season and your location. In winter the days are shorter (about 10 hours), in summer they are longer (about 14 hours). In spring and autumn, the day length is approximately 12 hours, especially in the period close to the solstice (end of March and end of September).

3. Divide the sun's path into segments:

Look at the equator and imagine the arc of the sun moving from East to West, beginning and ending its course on the horizon. Visually divide this arc into equal segments, the number of which will match the number of hours daylight hours. For example, if you believe that the approximate length of a day is 12 hours, then you should divide the arc by 12 equal segments: 6 will be located on the eastern half, 6 on the western.

4. Determine which segment the sun is in:

It won't be hard to determine. As mentioned above, one segment is one hour. Therefore, the number of all segments, starting from the east side, to the one in which the sun is now located, will correspond to the approximate time. The rest of the segments on the west side will tell you how many hours are left until sunset.

II. Determining the time by the moon

1. Find the moon:

If the moon is full, follow the same instructions for telling the time from the sun. If you have a new moon in front of you, then this method will not work.

Two stars in the constellation Ursa Major are located on the same line with the North Star. This line will act as a clock hand with the North Star at the center of the visual clock. Looking north, 12 would be at the top of the clock and 6 at the bottom. Now let's use our imagination to draw a circle with these hour markers. What time is it now? Suppose the "hand" shows 2:30. This is an approximate time.

For example, if May 7 is on the calendar, then you need to add 2 hours to the estimated time. We get 4:30. To achieve accuracy, add or subtract two minutes for each day after or before the 7th of the month. For example, today is February 2 - one month and five days until March 7. Thus, you must subtract one hour and ten minutes from the time indicated in the starry sky 2:30. We get 1:20.

The reason we have to focus our attention on the date of March 7 is that on this day the sidereal clock shows exactly 12:00 at midnight, therefore, this is our reference date, against which we adjust the time on the sidereal clock.

4.Summer time:

It is also necessary to adjust the time depending on the time zone in which you are located, and if there is summer time. If you translated the hands to daylight saving time, then you need to add one hour to the approximate one. If you live near western border your time zone, add half an hour. Conversely, if you are near the eastern border of your time zone, subtract half an hour. Now you will be able to determine the time with relative accuracy.

Some useful tips:

• if you have necessary material and time, you can build a sundial.
• It will be quite difficult to determine the time from the sun if you are in a region where there is little difference between day and night. For example, when the sun does not set throughout the summer.
• Remember to adjust the time according to daylight saving time.
• Don't bother specifying the exact time as it also depends on the latitude and longitude of your location.

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You can quite accurately determine current time. When calculating, be guided by the following considerations: at six in the morning the sun is in the east, at nine in the morning - in the southwest, at noon - in the south (shadows are the shortest at this time), at three in the afternoon - in the southwest. At six in the evening the sun is in the west.

If you happen to be in the circumpolar, where the solar disk is visible at night, then to determine the time, remember that at midnight the sun is at its lowest position above the horizon.

If you have a compass with you, you can also accurately determine the time by the sun. To begin with, remember that the sun's disk moves across the sky at a speed of 15 degrees per hour.

Measure the azimuth to the sun. To do this, first orient the compass by setting the zero division in the direction indicated by the compass needle. The angle between the zero division and the direction to the sun, measured in the direction of the clock hand, will be the azimuth to the sun.

Divide the resulting azimuth value by 15. For example, the azimuth to the sun was 90 degrees. By dividing 90 by 15, you get 6 hours. When making calculations in Russia, take into account the daylight savings time. To do this, add one hour. In addition, many countries have daylight savings time, so you need to add one more hour to the result.

Sources:

• Orientation
• Tarot Card Timelines

Today, without a weather forecast, many people do not think of their lives. It is understandable: you always want to know what the weather will be like during the day. And if you need to know the weather while on a camping trip, where there is no radio and Internet, what should you do? Help folk omens based on observations of the environment natural phenomena and behavior of living organisms, plants. Such observations have been made since time immemorial.

Instruction

Information about expected weather conditions, which many representatives of the flora can give us, are quite accurate. So, for example, swifts and fly over, almost sliding on the surface of the water in the case when rain is approaching, even if there is not a single one in the sky. This is explained simply - the humidity increases, midges with heavy wings accumulate near the water. And followed by and.

Information about the expected weather conditions that many representatives of the flora can give us is quite accurate. So, for example, swifts and swallows fly low above the ground, almost skimming the surface of the water when rain is coming, even if there is not a single cloud in the sky. This is explained simply - the humidity increases, midges with heavy wings accumulate near the water. And the birds follow.

Bees are also very sensitive to weather changes. When the bees become lethargic and fly as if reluctantly, beekeepers immediately make a “diagnosis” - to be bad weather.

Black-headed and river gulls can become peculiar barometers for the observer. If the weather is good, they can be seen on the water. But when the seagulls suddenly begin to walk along the sand near the shore, that the fish goes to the depths, sensing the impending bad weather. Seagulls have nothing else to eat on the water, so they move to the sand.

Black-headed and river gulls can become peculiar barometers for an observant person. If the weather is good, they can be seen on the water. But when the seagulls suddenly begin to walk along the sand near the shore, this means that the fish goes to the depths, sensing the impending bad weather. Seagulls have nothing else to eat on the water, so they move to the sand.

But here are a few signs that say that the weather is going to be clear, warm and dry: if the day was clear and the night is cold, the weather will change for the better. If abundant dew is observed, the wind intensifies during the day and subsides by night, the day is ahead. High skies deep blue, golden, yellow or even pink color Dawns, cumulus clouds following the wind, and night fog are signs of good and dry weather. It will be warm and dry even if the spider begins to weave a network intensively.

But here are a few signs that say that the weather is going to be clear, warm and dry: if the day was clear and the night is cold, the weather will change for the better. If there is abundant dew in the morning, the wind intensifies during the day and subsides by night, a clear day is ahead. High dark blue skies, golden, yellow or even pink dawn, cumulus clouds following the wind, and night fog are signs of good and dry weather. It will be warm and dry even if the spider begins to weave a network intensively.

The deterioration of the weather portends a sharp warming towards the night, after a clear and cold day. Crowns around the solar disk speak of impending rain. If the sparrows sit pompous, this also indicates the imminent rain. When ravens rise under the clouds and swifts fly low - to bad weather. Warming immediately after the rain heralds a cloudy day. If the night is bright, quiet and there is no dew in the morning, the day will be rainy.

A cold snap portends a red fire in the stove, a clearing closer to the night after cloudy weather. When sparrows hide in brushwood - to the cold, when the bullfinch whistles - to the coming winter. And if “earrings” appear near the moon, this indicates the approach of frost and blizzard.

Sources:

• How do weather centers determine the weather for several days in advance?

Unfortunately, modern urban residents are gradually losing their orientation skills. In case of extreme situations (a person is lost in the forest, for example), you need to know the elementary rules in which direction of the world he should move.

Instruction

Azimuth can also be defined on . To do this, put a compass on the side edge of the map, rotate the map 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 with the object you need to come to. Then move the compass so that its center is on 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 point of standing on the subject of the terrain, is called the direct magnetic azimuth. To find way back, often use the concept of back azimuth, which is 180 degrees different from the direct one. To determine the reverse azimuth, it is necessary to add 180 degrees to the direct one if it is less than 180 degrees; or subtract if it is greater than 180 degrees.

Sources:

• Azimuths and movement along azimuths

Prayer (prayer) is one of the most important pillars of religion. Prayer is the duty of every Muslim who has reached the age of bulyug (puberty) and has a healthy mind. A Muslim is required to perform 5 prayers a day at a strictly defined time. Prayer times are determined mainly by the movement of the sun.

Instruction

morning prayer

Time morning prayer starts at dawn and lasts until sunrise. It is necessary to have time to read it before the sun rises above the horizon. Since it is forbidden to read prayers during sunrise, sunset and when it is at its zenith. If you start praying before sunrise, but during the prayer the sunrise begins, then such a prayer is considered invalid.

afternoon prayer

The time of the daily prayer starts from the moment the sun is at its zenith and until the shadow from the objects is equal to their double length, plus a shadow is added to this during the zenith.

Evening Prayer

The evening prayer time begins after the end of the afternoon prayer time. Lasts until sunset. It should be noted that the prayer is considered invalid even at sunset. But unlike the morning prayer, the evening prayer, during which the sun began to set, is allowed to be read, it will be considered valid.

Evening prayer

The evening prayer time lasts from full sunset to the complete disappearance of light in the western side of the horizon. It should be noted that in some regions of Russia in summer months the light in the west side does not disappear. In such cases, different timing rules apply.

There are many methods that can be used to determine the cardinal points and time from the shadow from the Sun. They are based on an understanding of how the Sun moves across the sky during the day and what direction the shadows of objects show in different time day, including noon, morning and evening. Next, we will consider the most famous of them, which will allow the traveler to navigate when the means of navigation are lost or the watch breaks.

In the northern hemisphere, such a shadow at noon points north.

It is necessary not only to memorize the methods, but also to understand the mechanisms on which they are built. It is in this case that you can always adjust the method to the conditions in which the person finds himself. If this is not done, then in some cases such ignorance can lead to errors and an emergency.

So, for example, in many Internet articles and textbooks, a method of orientation by the hands of a mechanical watch and the Sun is given, which we will discuss in more detail later. However, almost nowhere is it said that specifically in this version it works only in the northern hemisphere, and even then higher. tropical zone. If a person does not understand where the “legs” of this method come from, he can easily make a mistake and, once in the southern hemisphere, incorrectly determine the cardinal directions, as a result of which he will get lost.

So, what is this basic knowledge, without which it will not work to determine the cardinal points by shadow?

Theoretical basis

All working methods for orienting by the shadow of the Sun are based on proven facts. Let's analyze them in more detail.

Fact number 1. The sun always rises in the east and sets in the west. However, in high latitudes during the polar day, for several weeks it does not set below the horizon at all, and during the polar night it does not rise above the horizon.

Fact number 2. In the middle and high latitudes of the northern hemisphere at noon, the Sun is in a southerly direction, or, as they say, in the south. In the southern hemisphere, at the same distance from the equatorial line, the solar disk crosses the north direction at noon. At the equator at noon, the Sun is half a year in the north, half a year in the south, and two days a year it passes directly overhead. We discussed this in detail in a separate article.

Fact number 3. At astronomical noon, the shadow cast by vertically placed objects on a flat horizontal surface will be the shortest, since at this moment the Sun is at its zenith, that is, at the highest point of its trajectory in the celestial sphere.

Fact number 4. The sun moves across the sky at an angular velocity of approximately 15 degrees per hour.

Fact number 5. If you face north, then the south will be behind you, on the right - east, on the left - west.

Specifically, this scheme will only work in the northern hemisphere at medium and high latitudes.

Of course, you need to understand that it is not the Sun itself that rises in the east and moves across the sky, but such a visible movement is associated with the rotation of the Earth and the presence of an observer on its surface. But for simplicity, we will not talk about the rotation of the Earth, but about the movement of the Sun.

And now I propose to go directly to the methods of orientation by the shadow from the Sun.

How to determine cardinal points by shadow

So, as promised, let's look at some of the most popular methods.

Method number 1. By the shortest shadow from the pole. This method is based on the fact that shadows from objects are shortest at noon. So:

1. A pole is vertically stuck into a horizontal flat area.
2. Before noon, the end of the shadow cast by the pole is marked on the site.
3. Such notes are made at short intervals.
4. When the shadow begins to lengthen in the afternoon, all marks are connected by a smooth curve.
5. On the curve, find the point closest to the pole and mark it.
6. Draw a line from the pole to this point. This line corresponds to the north-south direction.
7. They stand on this line so that it is parallel to the feet connected together, and the morning marks are to the left. Now the north is in front of the person, the south is behind him, the east is on the right, and the west is on the left.

If from the moment of marking the first point the shadow began to lengthen, this means that noon has already passed, and you need to wait for the next morning to repeat everything again.

Most sun orientation methods will require additional alignments.

Method #2. With the help of the shadow from the pole in the center of the segment. This method is based on the fact that the Sun rises in the east and sets in the west, and the right side of the trajectory of its movement across the sky is a reflection of the left. For this method:

1. As in the previous method, a pole is vertically stuck into the platform.
2. In the morning, a mark is made on the site corresponding to the end of the shadow from the pole.
3. The length is measured from the pole to this mark.
4. Closer to lunchtime, the length of the shadow decreases, and then begins to grow again. The shadow is periodically measured. As soon as it becomes the same length as the morning one, make a second mark corresponding to the end of the shadow.
5. A straight line is drawn between the first mark and the second. This line corresponds to the east-west direction.
6. A person becomes so that the first mark is on his left, and the second on his right. Now we can say that in front of him is the north, behind him is the south, on the right is the east, and on the left is the west.

These two methods allow one to relatively accurately orient oneself by the shadow from the Sun at any point on the planet (except for regions near the poles and at the poles themselves) during daylight hours, but they require a lot of time, which makes them unsuitable for a person who needs to navigate on the way.

Method number 3. With the help of the shadow from the pole at two points. This method is based on the knowledge that the sun rises in the east and sets in the west, and the shadows of objects move from west to east, although not always in a straight line. To navigate this way:

1. As before, a pole is vertically stuck into a flat horizontal platform.
2. On the site, with a stone, a peg, or in any other convenient way, the end of the shadow from the pole is marked.
3. Wait about 15 minutes and make a second mark corresponding to the end of the shadow from the pole.
4. Now, if you stand with your left foot on the first mark, and with your right foot on the second, we will have the north in front of us, the south behind, the east on the right, and the west on the left.

This method, like the previous ones, can be used anywhere in the world during daylight hours, but differs from them in its speed. However, this method has problems with accuracy.

The fact is that the shadow from the pole in most cases draws during the day not a straight line, but a curved one, while in relation to the position of the pole this line can be either concave or curved, depending on latitude and time of year. If you do not take into account these points, you can get a huge error, so I will give my recommendations that will allow you to use this method with maximum efficiency. There are only two recommendations.

Recommendation #1. It is best to use this method in March and September. It gives maximum accuracy throughout the day on the days of the spring and autumn equinoxes, since it is on these days that the shadow "draws" a straight line. The further you move away from these days on the calendar, the greater the error will be.

Recommendation #2. It is better to navigate using this method in the middle of the day. On any day of the year, this method shows the best results at lunchtime. The farther from solar noon, the greater the error of the method. Moreover, the error can double if, for example, you orient yourself 3 hours before noon, and then repeat the measurements 3 hours after noon.

Method number 4. Orientation by shadow and clock. This method is based on the fact that at 12 noon the Sun in the northern hemisphere is approximately in the south, and in the southern hemisphere - in the north, at 6:00 - approximately in the east, and at 18:00 - approximately in the west. Accordingly, the shadow cast by a person falls in the opposite direction from the Sun.

So, for example, if at noon you turn your back to the Sun, then in the northern hemisphere the shadow will be directed to the north, in the southern hemisphere - to the south. If you turn your back to the Sun at 6 o'clock in the morning, then the shadow will point to the west, and if you do the same at 6 o'clock in the evening, then the shadow will be located in eastbound. Having thus determined one side of the world, then you can find all the others.

A typical pattern for the northern hemisphere.

If you have to navigate on the way, then there is no need to look for a flat area each time to stick a stick into it and wait a quarter of an hour after that. It is enough to orient yourself once, to understand which side the Sun is on and in the future to choose the path, relative to its position in the sky. For example, if turning in the right direction, a person sees the Sun on the right, then during the transition, he must keep it on the right. In this case, over time, you can make a correction for the speed of the Sun, and during the rest, specify the direction using the described method.

When applying this method, it is important to remember that in some countries the clocks are switched to summer time and that the Sun at noon in the region of the tropics and the equator can be both from the north side and from the south during the year, which we talked about in a separate article . In addition, in it we also talked about other effects that affect the position of the Sun at noon, and therefore negatively affect the accuracy of the described method.

Method number 5. Orientation by the shadow of a match and a mechanical clock with arrows. This method is described in some military textbooks and is based on the understanding that in the northern hemisphere the Sun moves clockwise across the sky at an angular velocity of 15 degrees per hour. In order to navigate this method in the northern hemisphere:

1. The clock is placed horizontally with the dial up.
2. A match is applied to the side of the clock perpendicular to the dial. It is applied between the hour hand of the watch and the number "12" on the dial. So, for example, if the clock shows 8:00, the match is located near the mark "10", if the clock shows 20:00, then near the mark "4".
3. The clock turns with the match until the shadow from the match crosses the center of the dial.
4. When the shadow of the match matches the center of the dial, the number "12" will show the approximate direction of south.

This method works well only in those cases when the Sun, passing its highest point appears to be low above the horizon. The higher it is at noon, the more error this method will give.

The fact is that the speed of the projection of the Sun onto the horizon not only does not coincide with the angular velocity of the Sun, but also differs during the day. These differences are greater, the higher the solar zenith.

That is why this way orienteering is best used at high latitudes. In mid-latitudes, it is better to use in winter time year when the sun is at a low altitude above the horizon. In the tropics and at the equator, this method is usually not used, since here the Sun is high above the horizon at any time of the year, which means that the errors will be very large.

In this method, as in the previous one, you should take into account the change of clocks for daylight saving time. Other nuances are usually not taken into account, since the method still gives a fairly large error and is intended primarily for an approximate finding of the cardinal points.

In principle, you can slightly reduce the error by raising the edge of the dial, on which the number “12” is applied, at an angle equal to the difference of 90 degrees and the latitude of the area in which the person is located. For example, for a latitude of 35 degrees, the watch needs to be raised to an angle of 55 degrees. But, as my practice has shown, in some situations such an inclination not only does not reduce the error, but also increases it, since it is already difficult to position the match exactly perpendicular to the dial, holding it with your fingers, what can we say about the option with the inclination of the dial. But, among other things, the result of orientation will depend on the accuracy of the installation of the match.

In the southern hemisphere, this method needs to be changed, otherwise it will show results far from the truth. Personally, in this case, I imagine a dial with numbers located counterclockwise. Accordingly, if the clock is 10 o'clock in the morning, I imagine the hour hand pointing to the number "2", if the clock is 16:00, then I imagine the hand pointing to "8". Then I proceed as described in the method, but focusing not on a real arrow, but on an imaginary one.

This method is good for approximating the cardinal directions and usually gives the largest errors compared to the methods discussed earlier. But unlike them, it allows you to orient yourself within ten seconds, which is very practical and allows you to determine the cardinal directions almost on the go.

How to tell time by shadow

Shadow timing methods are based on the same knowledge as orientation methods.

The sundial is one of the most ancient instruments that allows you to determine the time of day by the direction of the shadow.

There are many ways to tell time from the shadow cast by an object that the sun is shining on. We will analyze some of them, but before that, we note that in these methods, in order to improve accuracy, it is necessary to take into account the factors that affect the discrepancy between astronomical and "terrestrial" time.

Method number 1. By the shortest shadow. On a flat horizontal platform, a vertically placed flat object, such as a dug-in pole, will cast its shortest shadow at 12 noon.

Method #2. East and West. The shadow will "point" west at about 6 am and east at about 6 pm. This method is the more accurate the closer the day on which you are trying to determine the time to the date of the spring or autumn equinox.

Method number 3. North and south. The solar disk will cross the north or south direction (depending on the hemisphere, and in the tropics and at the equator - on the time of year) at 12 noon.

Separately, you need to tell about the Arctic. In the northern hemisphere during the polar day, the Sun will cross the south direction at 12 noon, but it can also cross the north direction without dropping below the horizon, which will correspond to 12 noon. In the southern hemisphere, the opposite is true: the Sun will pass through the north at noon, through the south at midnight.

Method number 4. By shadow corner. This method determines the angle between the shortest shadow of a pole stuck in the ground, which corresponds to solar noon, and the shadow at this moment time. This angle is divided by the speed of the Sun in the sky - time is obtained. If the shadow is to the west, that is, noon has not yet arrived, then the resulting time is subtracted from 12 noon, if to the east, then it is added to 12 noon.

For example, at the mid-latitudes of the northern hemisphere, the shadow currently points to the northwest, and the angle with the north direction (the direction of the shortest shadow) is 30 degrees. We know that the sun's shadow moves from west to east. average speed 15 degrees per hour, and also that at 12 noon the shadow should point north. From all this, we calculate how long the shadow will point to the north: 30/15 = 2 hours. This means that there are still 2 hours left until 12 o'clock in the afternoon, which means that the clock at this moment of time is 12–2 = 10 o'clock in the morning.

The latter method works well at high latitudes (best during the polar day near the poles), while near the equator it gives very large errors and is not recommended. However, of all the methods described earlier, this one allows you to determine the time not only at 6 am, 6 pm and noon, but at any time in the middle of the day.

Of course, one sunny day can be spent making a primitive "disposable" sundial by sticking a stick in the ground and making marks at the end of the shadow every hour. Such clocks will show a fairly accurate time for several weeks after, until the solar zenith shifts vertically by a considerable distance. But this method will require an extra day and normal hours, which makes a little sense. What's the point of making a sundial when there's an ordinary one?

In fact, there are much more ways to navigate and determine time by shadow, but it makes no sense to describe them all. Today I only tried to highlight the essence of these methods, the mechanisms underlying them, and demonstrate all this using popular methods. Understanding these mechanisms, everyone will be able not only to use those described and check for performance found in various sources methods, but also to come up with their own, convenient in a given situation.

If we talk about the mentioned methods, then it will not be possible to choose the best one: each of the methods has its own advantages and disadvantages. Therefore, it is so important to use them all, choosing the best one for the prevailing conditions.

An interesting video: and another way to determine the time without a clock ...

Although, unlike space, in time, people can only move in one direction and at one speed, the ability to navigate in time has not bothered anyone yet. Watches, like any human-made mechanism, break too often to be relied upon outside the reach of a watchmaker. And the sun, moon, stars show time for billions of years without stopping and never once failed.

Let's start with a few numbers. The Earth moves at a speed of 29.8 km/sec in an orbit 930 million km long. The tilt of the earth's axis relative to the plane of rotation is 66° 5″. It determines the maximum angle of elevation of the Sun above the horizon and leads to the change of seasons. The period of revolution of the Earth around the Sun is 365 days and 6 hours. These same 6 hours lead to the need to arrange a leap year every 4 years.

The duration of the true (solar) day, i.e. of the day along with the night, during the year it changes somewhat depending on the time interval between the returns of the Sun to the meridian. The longest true day occurs on December 22, they are 51.2 seconds longer than the shortest true day on June 22. Well, the truth is that such accuracy is needed more in an observatory than in a forest.

21 March The sun is at its zenith at the equator, it rises exactly in the east and sets exactly in the west - this is day spring equinox, the astronomical beginning of spring "morning of the year".

22nd of June- the day of the summer solstice. The sun departs from the equator to the north by 23’5″ this day is the longest, the sun rises to the maximum height for this latitude.

Everything is very simple. To conduct accurate observations of the Sun and determine the date, it remains only to build something similar in size to Egyptian pyramid and you will be perfectly oriented in months, weeks and even days.

To determine the hours and minutes, you can get by with simpler devices.

Determination of time by the sun

• 6 morning in the East
• 9 morning - in the Southwest
• 12 - in the South, the shortest shadow
• 15 - in the South-West
• 18 - in the West
• 24 - the sun is in the North, do not rush to smile, the sun is not visible everywhere “at night”. In the circumpolar regions at midnight, it simply occupies the lowest position above the horizon.

In the equatorial regions, the opposite is true. Determining west or east at sunset or dawn is very simple. But at noon it can be both in the north and in the south.

Determining the time by the sun and compass

Just remember that the Sun moves across the sky at a speed of 15 degrees per hour. In order to determine the time using a compass, we measure the azimuth to the sun, let's say it is 90 °. Then 90 ° must be divided by 15 ° per hour, we get 6.

For Russia, it is necessary to take into account the standard time, i.e. add 1 hour, in addition, now in almost all countries of the northern hemisphere on summer period summer time will be introduced, i.e. one more hour added.

So plus one hour (daylight savings time) and we get 7 hours. Or, for example, the azimuth on the Sun is 180 °, so the time will be 12h + 1h (daylight savings time) = 13h.

Determining the time by the moon

Some introductory information. The lunar month is somewhat less than usual for Europeans and is 29 days 12 hours 44 minutes, i.e. The phases of the moon alternate every 29.5 days.

New moon- the beginning of the month: in this phase, the moon is not visible

First quarter- the visible crescent moon is observed half a circle in the first half of the night, sets in the middle of the night.

Full moon- The moon is observed in the form of a disk-circle, it rises in the evening and sets in the morning, i.e. shines all night.

Last quarter- the moon is observed half a circle in the second half of the night, it rises in the middle of the night.

Determining the time by the moon and compass

Let the moon come. Let's direct the north on the compass limb to the Moon (letter C to the Moon), count the degrees from the northern end of the magnetic needle to this direction. We get the azimuth of the Moon (ex. 270) then divide it by 15 and add 1

We determine that the visible part of the Moon is 5 parts of its diameter, on the basis that the full disk is 12 parts. Then we add them 19 + 5 = 24 and this is the time we are interested in. If sum > 24 subtract 24 from it.

On the full moon, you should do the same. For example, azimuth = 90

7 + 12 = 19 - i.e. now 19 hours (7 pm)

And if the Moon is decreasing, we must do the same, but subtract the count in fractions of the visible disk of the Moon.

Orientation in time by the stars

Determination of time by the constellation Ursa Major.
Each star and any point in the sky makes a full circle in 23 hours and 56 minutes.

Sidereal days are the basic unit of time, and their duration remains constant all the time.

Sidereal time is unsuitable for calculation due to the fact that the beginning of a sidereal day during the year goes to different times of the day or night.

When the constellation is at the bottom conditionally corresponds to 6 hours. Arrow finest hours., because Since all the stars revolve in the sky not exactly 24 hours, but ~4 minutes faster, then the readings of sidereal hours decrease by 1 conventional hour every month.

Therefore, the hand of the dial of the star clock shows at midnight

• 6 standard hours September 22, 12 conventional hours March 22
• 5 standard hours October 22, 11 conventional hours April 22
• 4 standard hours November 22, 10 conventional hours 22nd of May
• 3 conventional hours December 22, 9 standard hours 22nd of June
• 2 standard hours January 22, 8 conventional hours July 22
• 1 standard hour February 22, 7 conventional hours August 22

Let's say that a traveler decides to find out when midnight will be on November 7th. From the table, he will determine that November 7 is between October 22 and November 22, and on this day the hand of the sidereal clock should show 4.5 conventional hours.

Determining how much time is on the road is even easier. What time does the star clock show at the beginning and at the end

To convert star hours into real ones, you need to double the resulting number.

The hand of the star clock shows 1 arb. hour. According to the table, we find that at midnight 7.11. The hand showed 4.5 hours. Therefore, 4.5-1=3.5 standard hours. =7 hours

If the hour hand shows 6.5 arb. hours, then 4.5+12=16.5

16.5-6.5=10 arb. hours=20h i.e. 8 pm

Another way to define

Let's assume that the hand of the sidereal clock shows 6.5 conventional hours Let's find the ordinal number of the month since the beginning of the year with tenths elapsed from the beginning this month(every 3 days counts as 1/10 of a month) for example. September 12 \u003d 9.4 The resulting number is added to the indications of the star hour and multiplied by 2.

(6.5 + 9.4) * 2 = 31

This number must be subtracted from some constant for the celestial arrow.

Ursa Major has 55.3, i.e. 55.3 - 31 = 23.5

If after subtracting a number greater than 24, then you need to subtract 24 from it.

You can take other heavenly arrows, for example. Ursa Minor (the brightest star) its constant number is 59.1

Determining time by the movement of stars

The culmination of the North Star happens at different times of the year at different hours. Whether or not there is a climax is immaterial for timing, and so both climaxes can be generalized by adding one per hour (daylight saving time)

• Jan 15 and 5 July 7 and 19 hours
• Feb 15 and 15 Aug 9 pm
• 15 March and 15 Sept. 23 hours
• 15 Apr. And 15 Oct. 1 hour
• 15 May and 15 Nov. 3 hours
• 15 June and 15 Dec. 5 and 17 hours

Definition of time spans

This is the simplest. Imagine that the stars rotate on a dial with one hand and on which it is not 12, but 24 hours. Now, having a compass, we detect the azimuth to the Sun at the beginning and end of the time period, divide the difference by 15.

To get to the cozy corners of wild and unexplored nature, where you can find pristine peace and quiet, sometimes you need to go a long way. It is unlikely that in those places where a wide road has been drawn, it is worth laying a route in search of a relaxing holiday. To get to the desired goal and find the way back, you need to learn how to determine the direction (orientation) by the sun and stars.

On all four sides...

The main directions in geography are tied to the cardinal points. North and south are determined according to the poles of the Earth. East and West - in relation to the direction of rotation of the planet. Conventionally, on maps, north is at the top of the map, south is at the bottom, west and east are on the left and right, respectively. The four directions principle was milestone mankind in the knowledge of the world. On old maps the south direction was chosen as the main one, since it was easier to calculate by position. It was also easy to calculate the approximate western and eastern directions - at the place of sunset and sunrise, by the method of orientation by the sun.

With a person, they still use the principle of four sides - “left”, “right”, “front”, “rear”. This type of orientation is relative to the location of the person and the directions are not tied to the cardinal points.

compass orientation

If you have to orient yourself in the forest, the most reliable way- Use of a compass. In order for its readings to be accurate, it must be kept away from electronic devices, metal objects and magnets. Before you navigate the terrain, you need to set the compass to a horizontal position and remove the stopper from the arrow. The arrow after a while will take the position "south-north", showing the northern direction with the red end. If you stand facing this direction, then the east will be on the right, and the west on the left. In order not to go astray, it is necessary to check the correctness of the chosen direction of your movement more often.

Orientation on the map

On geographical maps special meridian lines are applied, which are oriented "south-north". Therefore, before using the map, lay it horizontally on a flat surface, on one of the meridian lines. Or the second option - next to the right (or left) edge of the map we put a compass ready for work and orient the map so that the "south-north" lines on the map and the direction of the compass needle coincide. The card is ready to use.

Going on a trip, try to understand how to navigate the terrain without such useful devices.

Using the watch for orientation

If you have a compass or a GPS navigator, then this can greatly help you navigate in the forest. But these useful devices are not always available, unlike wrist watch with arrows or arrow clock widget on the smartphone screen. For orientation, only the hour hand is enough. If there is an electronic clock or another way to determine the current time, then you can mentally imagine the clock and the direction of the big arrow of your virtual clock can be replaced with a finger. Next, your mental or real must be placed in a horizontal position.

Orientation by sun and clock

To determine the direction of the cardinal points, you can not use the clock, do it approximately, "by eye". But the result with the clock will be much more accurate. Orientation by the sun and the clock is based on the fact that the position of the sun during the day changes along a certain trajectory, and knowing at what time where it should be, we can determine the cardinal directions.

Determination of the south direction

At noon, the sun is almost always in the south. That is, if hour hand stands at 12 o'clock, it points to the sun standing at its zenith, then this is the south direction. This direction at noon serves as a kind of reference point, which we will use in the future for orientation by the sun. During the day, the daylight makes one complete circle in the sky. During this time, the hour hand runs two circles. This principle is the basis for determining the south direction in any daytime. The clock hand moves exactly twice as fast as the sun and moves at an angle half that of the sun. For example, at three o'clock in the afternoon, the hour hand moves at an angle equal to 90 degrees, and the sun deviates 45 degrees during this time. The south will remain at the same reference point. Therefore, if the bisector (middle of the angle) between the current position of the hour hand and the twelve o'clock mark is directed to the location of the sun, then the 12 o'clock indicator on the dial will almost exactly point to the south direction. This is the essence of orientation by the sun.

Features in determining the direction in the morning and evening

Orientation by the sun and the clock differs in the morning and evening by the direction of the angle of deviation from the twelve o'clock mark of the dial. Before noon, we look at the angle counterclockwise, in the afternoon - clockwise.

This method of determination is only suitable for local time. If your watch is standard time, then there will be a small error - up to 10 degrees. For more accurate measurement you need to check the compass in advance and see what position the sun is at noon, and then take into account this error. Taking it into account, the direction to the south will not be at the twelve o'clock mark, but will differ by a small angle.

Features in determining the direction at different times of the year

When using solar orientation methods, small differences between summer and winter time must be taken into account. Usually, in warm months, the reference point can have a shift of up to two hours, which also adds errors in measuring the direction to the south: in winter it can be located in the direction of 13 hours, and in summer - 14 hours. In winter, the sun rises in the southeast and sets in the southwest. In summer, sunrise will be in the northeast and sunset in the northwest. Sunrise exactly in the east and sunset in the west occur only on the days of the spring and autumn equinoxes and September 23, respectively). If you live in middle lane Russia, then just remember that at about 8 o'clock in the morning the sun will be in the east, at two o'clock in the afternoon - in the south, at about 8 pm - in the west.

Determining direction by shadow

Experienced tourists often advise when orienting by the sun, especially in summer, not to look at a bright blinding star, but at the shadow of any vertically located object. At a time when the sun is exactly in the south, the shadow of any object will be the shortest and directed exactly to the north.

Determination of direction at night

The simplest method of determining the direction at night - finding the direction to the north using the North Star - seems to be known to anyone. Find this one of the most bright stars you can do this as follows: try to find the “bucket” of the constellation Ursa Major familiar from childhood, identify the two extreme stars on its edges, mentally set aside about five distances along the line between them. The difficulty is that the constellation at different times of the year and day can be deployed at different angles to the observer.

Determination of cardinal points by the moon

This method is based on the fact that full moon is always in a southerly direction, and the degree of its illumination depends on the position of the sun behind the observer - you. The moon is full - the sun is behind you, in the last quarter - the sun is on the left, etc.

If the moon is not completely illuminated, then you should mentally divide its disk into six parts and try to determine how many parts the sun illuminates. The same amount will be in hours between the directions to these two luminaries.

There is also the option of dividing the lunar disk into 12 parts. How many such smaller parts are illuminated by the sun, so many hours back or forward you need to set the clock and, taking the Moon for the Sun, determine the direction to the south in the same way as in the daytime.