How to make a sundial (3 photos). How to make a sundial (3 photos)

On the eve of summer, the sun, the summer season, gardening and all that, I want to offer you step-by-step instructions on how to make a horizontal sundial on your site. Finding out the time from them is sometimes even more convenient than using a mobile phone (because the phone is not always with you; hands are dirty; the sun shines from the screen).

The basis of the sundial is the gnomon. This is a stick, the shadow of which will show us the time. The more accurately we orient this stick parallel to the axis of rotation of the Earth (how to do this - see paragraphs 1, 2, 3 below), the more accurate the device will be. As a gnomon, any flat stick, similar in size to a handle from a shovel, will fit (you can use the handle itself if you have an unnecessary one lying around).

We find a place where a lot of people and dogs do not run, and which you often pass by. The main thing is that it is lit by the sun most of the day. To do this, find the south (either orient yourself on Google Earth, or in the region of 12-13 hours turn to face the sun) and look for a place on the site with the most free (from roofs, trees, etc.) southern half of the sky.

Points 1 and 2 are devoted to finding the exact direction to the North. Yes, a compass can also be used for this, but we must remember that the magnetic declination (that is, the deviation of the compass readings from the real direction to the geographical North) in our country can reach 10, 20 or more degrees. In addition, you can catch a local magnetic anomaly. Therefore, the method of determining the North by the sun is more accurate and reliable.

1. By the time of true noon (solar climax, it is also mistakenly called "zenith"), we prepare a plumb line (for example, we hang a pebble / piece of iron on a rope and make sure that all this does not hang in the wind) and a horizontal platform on which the shadow from the rope is visible. I will describe the methods for calculating the time of true noon for your area below.

2. At the moment of true noon (it would be nice to synchronize the time with the Internet beforehand, for example, using the time.is service, or using the ClockSync android application), we mark the direction of the solar shadow of the plumb line, for example, using several pebbles that we lay out along the shadow. This is the exact north-south direction (meridian direction).

3. We calculate the tangent of the angle to the horizontal, under which the gnomon (that is, our stick) should stand. To do this, find out the latitude of the place, drive it into the calculator and press tan. For example, if the latitude is 56 degrees, then tan(56) = 1.483.

We multiply this number, for example, by half a meter (50 cm), we get 74 cm. We stick a stick into the ground, in the direction strictly to the north (we found it out in the last paragraph by a plumb line) from this place we put a pebble 50 cm from the place where the stick is stuck, and tilt the stick so that it passes over the pebble at a height of 74 cm. In figure 3 (and 3a for greater clarity) I showed a plumb line that descends from the gnomon and falls on the meridian line (the length of this plumb line in our example = 74 cm) . Instead of a plumb line, you can "shoot" with your eye, but it will not work out so accurately. And in this position, we begin to drive in a stick, from time to time checking / adjusting so that it passes over our "half-meter" pebble at a given height. As soon as the stick is firmly held, we can congratulate ourselves - the most important part of the work is done: we have oriented our gnomon parallel to the earth's axis. And, by the way, at the same time, he points to the North Star with good accuracy (you can check at night, "shoot" your eye along the stick).

4 and 5. The following positions of hour markers made by timer. It should be noted that although the figure shows 12 hours for the noon mark, in fact, civil time for it will be different. In order not to think about it, the easiest way is to mark the dial, approaching the gnomon at 13:00, 14:00 and so on, and simply mark the direction of the shadow. And the next day, from morning to noon, mark the remaining hour marks.

The hour markers themselves can be anything: you can drive in plates with numbers, you can lay them out with stones.

Calculating the Time of True Noon

I will list exactly what things happen at the time of true noon:
* the sun is exactly in the South (for our northern latitudes);
* horizontal shadows from vertical objects fall exactly to the North;
* the sun is at the highest point of its daily course;
* this moment is, with good accuracy, the middle between sunrise and sunset on that day.

Each meridian has its own moment of true noon. So, say, in comparison with the center of Moscow, true noon in the east of the city happens about 1 minute earlier, and in the west - a minute later. Here is the annual noon chart for the center of Moscow (for the UTC+3 time zone, in which Moscow has been permanently located since October 2014):

That is, on the meridian of Moscow, you can simply use this chart. The graph will turn out exactly the same shape in your place, only it needs to be shifted along the vertical axis by (D–37.6) / 15 hours, where D is your geographic longitude. For example, let's take Perm, its longitude is 56.2 degrees, we substitute it into the formula: (56.2–37.6)/15 = 1.24 hours = 1 hour 14.5 minutes. That is, in Perm, true noon happens 01:14.5m earlier than in Moscow, and according to Moscow time, 01:14.5m must be subtracted from the above schedule. For example, for May 22, we get 12h26.5m minus 01h14.5m = 11:12 Moscow time, add 2 hours (time zone difference between Perm and Moscow), we get 13:12. Remember this time to compare with the next method.

The second method is to find your locality on a weather website that lists sunrise and sunset times. For example, for the case of Perm, we open the Yandex weather site yandex.ru/pogoda/perm and see there Sunrise: 04:37 Sunset: 21:47, we find the arithmetic mean of these two times (04:37 + 21:47) / 2 = 13:12 . Same time as above.

The third method is the use of calculation programs. You can choose a program to your liking, I use my Day-night (at the link daybit.ru/video/video-i-soft.html you will find both a video on its use and the program itself), and it gives the time of noon for Perm = 13:11:45.

Notes

1. The above graph for Moscow is a consequence of the so-called Equation of Time - the difference between mean solar and true solar time. It should be noted that it is with the same amplitude as in this graph that the readings of your sundial will change. That is, up to plus or minus a quarter of an hour during the year. However, if you look closely, you can see that in the most interesting summer time for us, the fluctuations are not so large, and fit into plus or minus 5-6 minutes. Sometimes, when they want to get minute accuracy, a schedule of corrections is specially drawn up for the sundial during the year.

From this graph, for example, it can be seen that if you marked your sundial in mid-June, then by mid-September it will be 5 minutes faster.

2. Why not just use a vertical stick? Why bother with its tilt and its parallelism to the Earth's axis of rotation? The fact is that a watch made with a vertical stick will sooner or later show a noticeably wrong time. So, a clock made for a vertical stick in June will lie in September for 1 hour in the mornings and evenings. Read more sundial-ru.livejournal.com/2337.html

3. If you want, you can immediately calculate the dial for your area using, say, the Shadows shadowspro.com program, take the angles from this calculation and immediately measure them on the ground, instead of running all day and marking the sun's shadow.

Have you ever found yourself in a situation where you needed to know the time, but, unfortunately, there was no such possibility.

If one day you find yourself in a place where nothing and no one can tell you what time it is, the building sundial will be very helpful. By the way, this activity will not take you much time and effort. So, for a sundial, we need:

• a small piece of land with a flat surface;
• stick (which will cast a shadow);
• pebbles;
• rope (which will help draw a circle).

1. Clear a place for a sundial (it should not have any vegetation or irregularities in the form of stones) and stick a stick (gnomon) in the center.

2. Determine which side is North. If you place pebbles throughout the day where Sun casts a shadow from the tip of the gnomon, the pebbles will describe a hyperbole, and the North will be on the side where the shadow is the shortest. But for greater accuracy, first it is better to determine the position of West and East. Draw a circle around the stick stuck into the ground, the radius of which is set by the shadow falling from the gnomon early in the morning. After that, you have to wait until noon, when the shadow barely touches the circle. We connect these points with a line, which we will call the East-West line, since one of its ends is directed to the East, the other to the West. And the line perpendicular to the first will indicate the position of the North and South. We will call it the North-South line.

3. Draw another circle (its size will depend on how big you want to make the sundial), in the center of which there will be two intersecting lines: East-West and North-South. Presumably, its radius should be at least as long as the shadow from the gnomon.

4. Mark every 15 degrees on the circumference with stones. Start by dividing the arc between East and North into two equal parts, then divide each part into three equal segments. As a result, on a circle sundial you should get 24 identical parts.

5. Determine the approximate latitude of your location. This can be done using the Internet or, being in the northern hemisphere, you should find out how high above the horizon is the North Star. It is located at the end of the "handle" of Ursa Minor.

Having learned the latitude, mark this point on the circle with a pebble. You will find it by plotting the angle of the corresponding latitude degree (counterclockwise) relative to East.

6. Concerning the stone indicating the latitude, draw a perpendicular line, which should extend all the way to the North-South line.

7. Draw an ellipse with small axes at each point and longer axes where it intersects the East-West line. The point where the ellipse intersects the North-South line will indicate 12:00 o'clock, and the East-West line will indicate 6:00 o'clock (on the west side) and 18:00 (on the east side).

8. Extend the North-South line from one end beyond the 15 degree mark to the ellipse and place a stone at the intersection with it. This is how we got the clock (see the picture. Marks of 15 minutes are added on it. This can be done by dividing each hour into 4 parts).

9. Place a stick firmly in the center of the constructed clock, the full name of which sounds like an analemmatic sundial. Remember that the exact position of the stick in the center (gnomon) changes depending on the season (+/- 23.5 degrees) relative to the North-South line.

10. Watch for which numbers the shadow cast from the gnomon indicates. This number will be the initial step in the definition of time. You should then correct the time for your location's latitude and daylight savings time (if applicable).

The history of sundial already has more than one millennium, but when exactly people began to use them is not known for certain. It has been established that in ancient Egypt, Babylon and China, such devices were used earlier than a thousand years BC. The first mention of determining the time by the sun's rays using a special device dates back to 1306-1290. BC.

Any sundial has a dial with a scale and an hour hand called a gnomon. At the same time, according to their orientation, sundials are divided into horizontal, vertical and equatorial. There are many modifications of them, such as stepped, ring, plate, mirror, bifilar and others.

A sundial is not necessarily a disk having a perpendicular gnomon. So, the dial can be a hemisphere or a ring. The universal equatorial clock can be used at all latitudes. Their design involves two rings perpendicular to each other and a gnomon. To determine the time, you must set the latitude on the scale on one of the rings and set the date. Then the clock is rotated around a vertical axis until a point showing the time appears on the dial. At this moment, one ring is oriented north along the meridian, and the second is parallel to the plane of the equator.

In a horizontal sundial, the plane of the dial is not perpendicular to the gnomon, which should be parallel to the earth's axis, and also point to the north, that is, the angle between them is equal to the latitude of the area. The horizontal clock is convenient and easy to install. To use them at a different latitude, it is enough to change the angle and direct the gnomon to the north.

In ancient Egypt, different models of sundials were constructed, for example, with a horizontal scale that made an angle of 90 degrees with the plane of the local meridian, and their gnomons were obelisks, the height of which usually reached several meters. In order to find out the time from them, the direction indicated by the shadow from the gnomon was used. Another sundial, called "step", had two surfaces, tilted to the east and west, and divided into levels. When the sun moved, the shadow moved from one step to another, and time was determined by its length.

In Central Europe, until the 15th century, wall-mounted vertical sundials, the gnomon of which was horizontal, were widely used. True, the accuracy of determining the time on them was low.

At the same time, there were several variants of road chronometers, for example, ring sundials. They were two rings, in one of which there was a hole for the passage of the sun's ray, and the scales of months and hours were applied to the other. There were also plate clocks, the constructive solution of which included two, sometimes three, identical plates, which had a rectangular shape and were fastened together, while a compass was installed on the bottom.

There is a description of medieval octagonal sticks with four through holes in the handles, into which metal rods had to be inserted to determine the time. Around the same time, window chronometers appeared. They were vertical. The principle of operation of the sundial was to use the window of the town hall or temple as a dial with a translucent scale applied. This made it possible to find out the time while being indoors. A mirrored sundial used a sunbeam reflected by a mirror, which they directed onto the wall of the building where the dial was located.

The oldest mechanism for determining time. Sundial- the simplest device, but it contains the knowledge and observations of our ancient ancestors. Currently sundial used as landscaping. For example sundial parents teach their children the structure of the solar system, and the building itself DIY sundial- the most exciting activity for our children, for example, being on the beach. In the manufacture sundial you need to know some points and features of their design, which we will discuss in this article.

What is a sundial made of?

Sundial consist of a pointer hand that casts a shadow (this hand is called a gnomon) and a sundial dial. Time by sundial determined by the shadow cast by the gnomon on the dial. Everything is simple, but there are some features. Clock face sundial divided into 24 hours instead of 12 hours as in conventional mechanical watches. The dial or gnomon should be tilted above the plane. Sundial do not take into account daylight savings time. Sundial works only in clear or partly cloudy weather during daylight hours. That's all the restrictions sundial.

There are several types sundial. Let's deal with them in order.

You can do it right on the sand on the beach. To begin with, we need to know two things: what latitude we are at and where north is. If the second part can be established by selection, then the first will have to be prepared. So, we have a compass and we know our latitude (St. Petersburg - 60, Moscow - 55, Nizhny Novgorod - 56, Yekaterinburg - 56, Sochi - 43, Rostov-on-Don - 47, Novosibirsk - 55, Vladivostok - 43 degrees north latitude). If we make a dial sundial on a portable surface - draw a circle and divide it into 24 parts. If we make a sundial on the ground, draw a circle, insert a stick (gnomon) into the center of the circle and tilt it to the north so that the angle between the surface of the earth and the gnomon is equal to our latitude, draw a line from the lower end of the gnomon exactly to the north - it will be 12 hours of the day according to astronomical time. We draw the remaining lines, dividing the entire circle into 24 equal sectors. Each sector sundial equals 15 degrees.

Here we are in for an ambush. After a competent division of the dial and the inclination of the gnomon, the time showing sundial may differ from the time shown by local television. The problem lies in the standard time and time zones, which were artificially created for convenience. A portable watch face will easily solve this problem, just turn it around until the time is right. With a clock drawn on the sand a little more complicated, this point must be taken into account when starting to paint the dial. For example, you can postpone the marking of the dial until 12 o'clock, when we will determine the north without a compass and accurately draw the main axis of the dial of our sundial. If there is no time to wait, and creativity is rushing out of you, draw a dial sundial in a draft version and adjust your dial for the error that you got.

In our latitudes sundial they work in the midst of summer hours from 8 am to 8 pm, so it is almost pointless to race numbers between these values. Because of this, often on a round dial, the base of the gnomon is shifted down.

The same horizontal clock, only the gnomon is set clearly vertically, and the dial itself is inclined to the earth's surface at the latitude angle of the place where such clocks are installed.

Vertical sundial.

Vertical Sundial usually attached to the walls of houses. The same inclined gnomon and a dial lined through 15 degrees.

Usually in cities they make a mixed type sundial, i.e. the dial is tilted half the angle, the gnomon is tilted half the angle. Such a construction sundial look more spectacular, in fact, because of what they are made.

Building sundial with your own hands will really captivate your child and, in addition, expand his horizons.

The history of the sundial

Man invented a number of instruments for measuring time, for example, moon, water, candle clocks, which were used until the 18th century, then hourglasses and oil clocks from the 16th to the 18th centuries. However, due to their dependence on external conditions and their fluctuations, as well as due to technical imperfection, these means of measuring time have not found general application.

According to modern chronology, already 4000 years ago, clocks of varying degrees of complexity already existed everywhere. The Egyptians were the first to try to make them, who invented stellar hour charts, and it was possible to determine the night time by watching the rise of the stars. As for daytime, the late Egyptians invented shadow clocks. (sundial). The shadow from the transverse beam gradually crossed the row of marks from sunrise to sunset. A set of instructions for making such a clock was found in the tomb of the pharaoh.

Seti I, who ruled around 1300 B.C. Such simple shadow clocks were the forerunners solar.

Particularly favorable climatic conditions for measuring time with sundial had Egypt. News of the most ancient of the ancient Egyptian sundial refers to the reign of Thutmose III - the first half of the XV century. BC. One of the types of sundial was a stepped clock in the form of an obelisk with two inclined surfaces, oriented along the axis to the east - west and divided into steps. At sunrise, the shadow fell on the edge of the upper step of one of these surfaces - the eastern one, then gradually lowered until it completely disappeared by noon. Then, in the afternoon, the shadow reappeared at the bottom of the western surface, from where it kept rising until, at sunset, it touched the edge of the top step.

On the described sundial time was measured by the length, not the direction, of the shadow cast. However, the Egyptians had a sundial with a scale to determine the direction of the cast shadow. The famous Roman architect and architect Marcus Vitruvius, who worked during the reigns of Caesar and Augustus, describes in his essay "Architecture" at least 13 types of sundials.

These include horizontal hollow hemispherical sundial- the so-called hemispheres. The inner surface of the hemisphere represented the celestial hemisphere with an equatorial line, two solstice lines and a twelve-hour time scale. The invention of such clocks is attributed to the famous ancient astronomer Aristarchus of Sames, who lived in 320-250 BC. BC who also made sundial with semicircular dials divided into five parts (hours) of unequal length. in perfection of the Greek sundial The well-known mathematician, doctor, founder of Greek astronomy, Eudoxus of Knidos, who lived in 408-356, also took a great part. BC. The sharp end of the gnomon, which originally served the Egyptians to clearly limit the shadow on the scale, was later replaced by the Greeks with a small round hole, the so-called solar eye, which threw a small point of light on the scale. In addition to the horizontal clocks mentioned above, the Greeks also had more advanced vertical sundial, the so-called hemocycles, which they placed on public buildings. All ancient sundials were based on the simple principle of the gnomon, in which the length and direction of the cast shadow depended not only on the position of the Sun at a given moment in the sky, but also on the season.

With the Roman method of dividing day and night into 12 hours, daylight hours were lengthened in spring and summer, and shortened in autumn and winter. The ancient sundial, due to its imperfection, indicated such time, the main feature of which was that under the influence of the changing inclination of the Sun, the length of day and night hours changed during the year. Later antique and many medieval sundial had curvilinear scales, eliminating this drawback. Such clocks, with more complex and more accurate time scales calculated for quarterly or monthly intervals, were used until about the 15th century. A new era in the development of sundials was opened by an important invention dating back to 1431. Its principle was to set the shadow arrow in the direction of the earth's axis. By this simple innovation, it was achieved that the shadow of the arrow, called the semi-axis, after this innovation, rotated uniformly around the semi-axis, turning every hour by 15 degrees. This made it possible to introduce a uniform time that could be used throughout the year, and the segments corresponding to the hours were of the same length regardless of the changing height of the Sun. The next step in development sundial a sundial with a compass. To the first creator sundial with a corrective compass applies astronomer and mathematician

Regiomontan. with a dial parallel to the plane of the earth's equator, and a gnomon perpendicular to it, were, in fact, the simplest clock with a uniform time scale. The creators of such watches usually proceeded from the fact that they would be used in different geographical latitudes. Sometimes such watches had a geared hand and a small dial with a hand for counting minute intervals with an accuracy of 1 to 3 minutes. Such clocks were called heliochronometers.

There were also equatorial clocks arranged in such a way that their dial indicated directly the mean solar time, not local solar time like a regular equatorial clock. Varieties sundial were very diverse. Interesting roundabouts sundial- one of the options for traveling sundial, which very often served as a decorative pendant at the same time.

The main part of such sundial there was a brass ring a few centimeters in diameter with another movable ring provided with a hole for the sunbeam. On the outer surface of the main ring, the initial letters of the names of the months were usually engraved, and against them, on the inner surface, there was an hour scale. Before measuring, it was necessary to turn a smaller, usually iron, ring so that the hole for the beam lay at the name of the corresponding month. When measuring time, the clock was held in a position that allowed the sun's beam to pass through the hole in the scale. The so-called equatorial rings were built on a similar principle - similar clocks, on the main ring of which there were two more circles intersecting with each other. Later, a new version appeared with a cross member instead of the third ring.

On one side of this crossbar were indicated the months, and on the other - the signs of the zodiac. In the middle there was a jumper with a small hole for the passage of the sun's beam. The correct position of these clocks when measuring time was when the sun's beam passing through the hole fell on the center line of the equatorial circle. In conclusion of this section, I would like to dwell briefly on one of the models of road sundial used by Indian travelers. They were wooden octagonal sticks with a metal tip 160 cm long with carved hour scales. A rod about 15 cm long was inserted into the hole above the scale for the corresponding month so that its tip, when the stick was in a vertical position, cast a shadow on the scale. There should have been 12 scales on the stick. Since the same conditions were valid for the days removed from the solstice at the same time, it was enough to have 8 scales. These watches received the name ashadah according to the season (June-July) in which travel was made. Sundial have never lost their significance and continue to be designed even today. The Romans improved upon the sundial we are familiar with today, and even made solar portable watch convenient for travel. They existed for millennia and remained for a long time a means of checking and coordinating for very unreliable wheel clocks, until they were finally superseded by the invention of the spiral spring as a regulator (1674), but we will talk about this below.

We examined the structure and functioning of a sundial, which has been improved and changed over the years. Sundial with a height-adjustable pole, compass, and minute scales were a simple and reliable solar time indicator, but they also suffered from some serious shortcomings. Their work was associated with sunny weather and with a limited period of work - between sunrise and sunset. Therefore, new devices for measuring time were fundamentally different from sundials. While the unit of time according to the sundial was derived from the rotation of the Earth and its movement around the Sun, it was necessary to create an artificial standard of the unit of time, for example, in the form of a time interval necessary for a certain amount of substance to flow out in a chronometric device.

A word of 6 letters, the first letter is "G", the second letter is "H", the third letter is "O", the fourth letter is "M", the fifth letter is "O", the sixth letter is "N", the word for the letter "G", the last "N". If you do not know a word from a crossword puzzle or a crossword puzzle, then our site will help you find the most difficult and unfamiliar words.

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Other meanings of this word:

• The oldest astronomical tool for determining the meridian - a vertical pillar on a horizontal platform
• The oldest astronomical tool for determining the meridian is a vertical pillar on a horizontal platform.
• the oldest astronomical instrument - a vertical pillar on a horizontal platform; serves to determine the moment of noon and the direction of the noon line (meridian) in a given place
• The oldest astronomical instrument, consisting of a vertical rod on a horizontal platform and used to determine the height of the sun above the horizon, the direction of the midday line in a given place, etc.
• The oldest astronomical instrument is a vertical pillar on a horizontal platform; serves to determine the moment of noon and the direction of the noon line (meridian) in a given place