Time, chronometers and longitude

The watch is over, eight bells have struck.
A new watch is starting.
Leave your beds for the glory of God!
An ancient song of the sailors

The bells chime the time

Ancient man, probably, already at a very early stage of his development, learned to count days and measure time according to the celestial bodies known to him.

The system of counting long periods of time, in which a certain order of counting the days of the year is established and the era from which the years are counted is indicated, is called calendar.

If there were any simple relationship between the length of the day and the length of the year, i.e., the time the Earth rotates around its axis and the time it rotates around the Sun, then counting the days in a year would not be difficult. The same is true for counting days in the lunar month. However, our solar system was formed in such a way that currently, with an accuracy of 0.1 seconds, the length of the year is 365 days 5 hours 48 minutes 46.1 seconds, or 365.2422 days, and the length of the lunar month is 29.5306 days. Comparing these numbers, it is easy to see that the ratio of the length of the year and the lunar month to the length of the day does not express any exact numbers, either whole or fractional. That is why it was not at all easy to develop a simple and convenient system for counting days. This can be seen from the fact that from ancient times to the present day hundreds of such systems have been invented, but none of them is considered good enough.

Egyptian priests, whose duties included observing the heavenly bodies, around 2000 BC. e. discovered the so-called Sothic period and determined its duration (1461). Observing Sirius (the Egyptians called it the star Sothis), which foreshadowed the flooding of the Nile, the Egyptians established the duration of the solar year at 365 days. In this calendar, the year consisted of 12 months, 30 days each. The error was approximately 0.25 days per year.

The Muslim calendar is based only on changes in the phases of the moon. This calendar was introduced in the 7th century. n. e. in some Muslim countries. Currently, in many countries of the Middle East, where Islam dominates, this calendar is used.

In Europe, according to the Julian calendar, the years were counted from the conventional date of the Nativity of Christ.

The first Russian handwritten calendar appeared in 1670, probably translated from Polish. The first printed calendar was published in 1686. However, only the calendar of 1714 can be called the first navigational calendar. It is remarkable in that the calendar and predictions of astrologers were excluded from it. The time of the phenomena given in the calendar was for the first time calculated according to St. Petersburg time, which meant an attempt to introduce a single standard time in the country. For the first time, tables of sunrise and sunset times were placed in the Russian printed calendar.

The calendar we currently use is not perfect, since the choice of the starting point (epoch) in it is arbitrary, and division into months of different lengths is not entirely convenient. It is important to remember that for the correct calculation of years, it is not important which event is taken as an epoch, but that the same specific date is taken as the beginning of the countdown. Many nations accumulated quite a lot of such dates.

Time was calculated according to the new style in Russia already at the beginning of the 18th century. The accounting of time (time), used in the fleets of many countries until the beginning of the 20th century, differed from the civil one and was called astronomical. If according to civil time the day began at midnight, then on ships it began at noon of the same day. It was convenient for navigators to start the day at noon: at the same hour they checked the time using a sundial and at the same time determined the latitude of the ship from measurements of the midday altitude of the Sun. This order of day counting among seafarers was introduced in the 15th century. with the beginning of the first overseas voyages, when only a sundial was used to calculate the ship's path and noon was a convenient moment for checking the time.

The Russian fleet used the so-called “ nautical reckoning”, in which the day began at half a day of the previous day according to the civil calendar.

In England, astronomical timekeeping was finally introduced in 1767, after the publication of the Nautical Astronomical Yearbook (“Nauutilas Almanac”).

In Russia, the “marine reckoning of time” existed until 1814, when the first translation of the English yearbook called “Marine Month Book” was published. The transition to the civil calendar in our country was carried out only on January 1, 1925, from that time the day began to begin at midnight for sailors.

The history of clocks is closely connected with the countdown of the beginning of the day at noon. It was at noon, at the moment of the culmination of the Sun, that the hourglass “started”. And the tedious counting of time until the next half day began. And so day after day, month after month. Ship clocks of the 15th-18th centuries are a whole set of glass vessels with sand (flasks). The main items in the set were considered to be four-hour flasks.

Every 4 hours, the watchman assigned to the clock had to turn over the hour bottles. This moment, for greater audibility, was marked by special blows to the bell (rynda) and served as a signal for a change of watch. The watchman still had hour and half-hour bells on his watch. When these bottles were turned over, a bell sounded every half hour (“the bottles were struck”).

The beginning of the watch was marked by eight “bells” - four double strikes on the bell. After the first half hour of a new watch, one “flask” sounded, i.e. one blow, after an hour - two “flasks”, after another half an hour - three “flasks”, etc. Nowadays, a special time service has been organized on ships and The radio sounds precise signals every hour, and the sound of ship bells can be heard in the roadstead.

They also used small “flasks” on ships: five-, three- and half-minute ones. They were used, for example, in astronomical observations or in determining speed by lag.

It was interesting to check the accuracy of the hourglass. To do this, they took a half-minute “flask” and the time of pouring sand was controlled by a “bullet on a thread” (a weight suspended on a thread 39.2 inches long, i.e. 99.6 centimeters), in 30 seconds it made exactly 30 swings ( fluctuations). The “bottle” verified in this way was used to check other “bottles”.

Hourglasses were popular in the navy. They were simple, cheap, quite accurate and were used on Russian ships until the end of the 18th century.

Discovery of the laws of the pendulum

One of the greatest creations of human hands - mechanical watches - invented in the XI-XII centuries. Like many other great inventions of the distant past, this one has many authors. One of them is considered to be Herbert of Aurillac, already familiar to us, who, in addition to improving the astrolabe, introduced “Arabic numerals” in Europe. According to some sources, mechanical watches with gear wheels first appeared among the Arabs, and from them they entered Europe through Spain.

At first, large tower and cathedral clocks were built, intended for secular needs. They were used to count the time of religious ceremonies. This is evidenced by the very name “clock”: in Latin clocca - bell. The first wheel clocks were bulky, poorly regulated, their movement was uneven and the watchmen assigned to them had to constantly align them with the Sun. The use of such watches on ships was out of the question. Therefore, preference was still given to ancient sand bottles. Even in 1533, when the art of navigation was already relatively developed and mechanical watches were well known, the previously mentioned Gemma Frizius wrote: “On long journeys, especially sea journeys, it is useful to use a large clepsydra (water clock) or an hourglass that can accurately measure time around the clock and thanks to which you can correct the errors of other watches.”

In the 15th century The design of mechanical watches was improved: instead of a weight that drove a system of wheels with indicators, a clock spring began to be used, which made it possible to produce watches in a desktop version of relatively small sizes.

Spring clocks were superior in accuracy to sand clocks, water clocks, and fire clocks, and they soon began to be used in astronomy. The first mention of this dates back to 1484, when Bernard Walter, a student of Regiomontanus, used a mechanical clock to measure the time interval between the moments of the emergence of the planet Mercury and the Sun. The clock installed in his observatory even counted quarter seconds. The famous Danish astronomer Tycho Brahe (1546-1601), who compiled a catalog of 1005 stars, also used wheel clocks in his observations. However, they did not satisfy him in terms of accuracy and reliability.

The need for more accurate clocks grew. However, for a long time mechanics could not find a way to regulate the speed of mechanical watches. The discovery of the laws of the pendulum by the great Italian scientist Galileo Galilei (1564-1642) helped solve this problem.

Galileo was born in the city of Pisa into a poor musician family. In 1574, the family moved to Florence, where Galileo studied at a monastery and was accepted into the monastic order as a novice. However, Galileo was not attracted to theological teachings, but to mathematics, mechanics, physics and astronomy. He soon left the monastery and in 1581 entered the University of Pisa. While still a student, he became interested in the problem of motion. Viviani, a student and first biographer of Galileo, says that in 1583, while in the cathedral, under the high arches of which the wind was blowing, twenty-year-old Galileo noticed how the church chandeliers, suspended on long chains from the ceiling, were swaying. Chandeliers were of different sizes and had different weights. To compare the vibrations of chandeliers, he began to measure the time of their swing using his own pulse. These observations led him to the conclusion that when the vibrations of the chandelier died down, that is, the swings became shorter, their duration did not change. It turns out, the observant young man decided, the swing period depends only on the length of the chain and does not depend on the shape and mass of the chandelier.

Galileo set out to explain the laws of motion of a pendulum and began experimental research. He established that the swings of the pendulum are very uniform and can occur for a long time, and their period does not depend on either the load or the amplitude of the oscillations. And if so, it means that by counting the oscillations of a pendulum, time can be measured.

“The oscillations of a pendulum,” Galileo wrote, “occur at certain times with such inevitability that it is absolutely impossible to force them to occur at other times except by lengthening and shortening the thread. Another feature, truly amazing, is that the same pendulum makes its oscillations with the same or very small and almost imperceptibly different frequency, whether the oscillations occur along the largest or smallest arcs of the same circle.”

The discovery of the laws of the pendulum helped Galileo solve a number of other important issues in mechanics and theory of motion, in particular, to explain the laws of the fall of bodies and their motion on an inclined plane, and to establish the independence of the occurrence of mechanical phenomena from selected inertial reference systems. Subsequently, he returned to these questions more than once. Shortly before his death, Galileo developed the idea of ​​creating pendulum clocks to his son Vincenzo. It consisted of the following.

With a pendulum AB a rod C was connected, its end entering the gap between the teeth of the wheel D, which had freedom of rotation around the axis E. With each swing of the pendulum back and forth, the rod caused the wheel to turn one tooth. The gear wheel was connected to a special counter that measured the number of oscillations of the pendulum. Galileo made calculations, but real clocks were never made based on them. Loss of vision prevented Galileo from realizing his idea. He entrusted his son to continue working on the pendulum clock. However, for various reasons, he was able to start work only in 1649, but suddenly died without completing the work begun by his famous father. A drawing of Galileo's pendulum clock design, which was published in one of the editions of his works, has survived.

The honor of inventing and creating pendulum clocks belongs to the Dutch mathematician and astronomer Christian Huygens (1629-1695).

Huygens was born in The Hague into the family of a prominent politician and writer, and received an excellent home and then university education. His teachers instilled in the gifted student the spirit of seeking new paths in science. The talented young man was greatly influenced by the famous scientists Descartes and Mersenne, who knew his father well. Huygens' scientific interests were varied. While still a student at Leiden University, he began scientific research in the field of mechanics and, in particular, research into the fall of bodies and questions about the center of swings. Later he became interested in optics and astronomy.

Two circumstances prompted him to start working on watches: the need for more accurate measurement of time during astronomical observations and the aggravated problem of measuring longitude at sea.

The principle of determining longitude was known to Hipparchus: the difference in longitude of two points corresponds to the difference in local times

while simultaneously observing the moment of any one event at these points. Hipparchus proposed to consider an eclipse of the Moon to be such an event, since it occurs at the same moment in time for all its observers on the earth's surface. However, Hipparchus did not know how to determine quite accurately the local time of this event at both points and how to transfer the local time of a point with a known longitude to a point with a determined longitude. A sundial, of course, was not suitable for this, since during a lunar eclipse the Sun is below the horizon. In addition, these eclipses occur quite rarely - no more than two or three times a year, and besides, it is very problematic to fix the exact time of its beginning or end at different points, since the boundaries of the shadow are very fuzzy and vague. Due to different fixations of the beginning and end of this phenomenon, time errors of several minutes are possible, and this leads to errors in determining longitude of several degrees, i.e., hundreds of miles.

This method began to be used at sea in the 13th-15th centuries, when they learned to determine local time using astronomical methods and the first tables and almanacs appeared with predictions of the beginning and end of eclipses at various points on the Earth. It is known, in particular, that X. Columbus used it. During the second and fourth voyages, using the almanac and ephemeris compiled by Regiomontanus, he determined longitude from lunar eclipses on October 14, 1494 and February 29, 1504. The error in longitude in the first case was 1.5 hours, and in the second - 2, 5 o'clock.

It is difficult to say what caused such a large error - errors in calculating the moments of the eclipse or inaccuracy of observations. It should be noted that even in Newton’s time the error in predicting a lunar eclipse was sometimes an hour or more, so at that time sailors were quite happy if they were able to determine longitude with an accuracy of two degrees.

Inaccurate navigation sometimes led to serious incidents. This was the case with X. Columbus, when, returning to his native shores after the discovery of America, he, having determined the latitude, could not say exactly where his ship was located - in front of the Azores or they had long been left behind. A strong storm aggravated the uncertainty, which forced X. Columbus, just in case, to throw a barrel into the ocean with a message about his discovery of the New World. Fortunately, everything turned out well, and the great navigator reached the shores of Spain. Here he became convinced that his assistants, determining longitude by the distance traveled, were mistaken in calculation by more than 400 miles!

In the process of development of navigation, navigation and cartography, there was a constant need to improve the accuracy of determining coordinates at sea. Going on long voyages, sailors of the 16th-17th centuries. They already had a whole set of navigational instruments and instruments: a compass, an astrolabe, a log, a lot and, of course, an hourglass. However, due to the fact that all the instruments were inaccurate, and the influence of wind and current was taken into account only approximately, ships often found themselves hundreds of miles from the intended location.

In 1567, the Spanish navigator Mendaña de Neira discovered the Solomon Islands, but due to an inaccurate determination of their location, they were then “lost” for two centuries and rediscovered only in 1767-1768. Bougainville expedition.

Sometimes it took whole weeks and even months to search for the shores, and they were not always successful. The whole trouble was that the sailors could not yet definitely answer the most important question for them: at what point in the ocean the ship was located. After all, if they could somehow measure latitude, at least approximately in clear weather, from the altitudes of the Sun or stars (in this case, of course, it was necessary to use a catalog of star declinations or solar tables), then they were not able to determine longitude at all (when moving east and Whether to the west, the picture of the starry sky remains unchanged) and relied only on a very approximate calculation of it according to compass and log data. For this reason, captains at that time often steered the ship not in a straight line - the shortest path from point to point, but by moving a chess knight. First, they descended or ascended along the coast to the desired latitude and only then turned east or west.

The problem of determining longitude has worried both sailors and scientists for many centuries, trying to solve this important problem.

In 1514, Johann Werner of Nuremberg (1468-1522) proposed determining longitude using the “lunar distance” method, based on the laws of motion of the Moon in relation to other celestial bodies. The Moon, due to its rotation around the Earth, quickly changes its position relative to the stars. If you calculate in advance for certain geographical places tables of distances of the Moon to the fixed stars for each day, hour and minute, then you can calculate the difference in longitude.

This idea was expressed earlier, in particular by Regiomontanus, but its practical development belongs to Werner.

The method consisted of measuring the distance between the Moon and one of the nearby stars using a city rod or some other goniometric instrument, and then using astronomical tables of star positions and an almanac with pre-calculated positions of the Moon to determine the difference in longitude. In other words, Werner proposed using the celestial sphere as a giant clock, with the Moon serving as the hand and the zodiac stars as the dial.

However, it was impossible to implement this method on the open sea in Werner's time due to the lack of sufficiently accurate goniometric instruments and corresponding astronomical tables. In the XVII-XVIII centuries. the theory of the motion of the Moon made it possible to determine its position with an error of about 2-3°, but it was necessary no worse than 2-3." The method of “lunar distances” began to be used in practice only in the 1760s after the invention of the sextant and the publication of the “Nautical Almanac” ( 1766) with tables of the exact positions of the stars and the distances from the Moon to the Sun and some zodiacal stars for every three hours for the entire year. The method required several simultaneous observations (the angular distance between the Moon and the star or the Sun, the height of the star or the Sun, the height of the Moon), accurate. determination from observations of local time and rather complex calculations to take into account parallax and refraction. In addition, it was possible to determine longitude in this way only with a clearly visible horizon. Because of these difficulties, the method could not be widely used.

Galileo proposed using the four satellites of Jupiter, which he discovered with

using the telescope he invented (1610). They occurred much more often than lunar eclipses (from one to three almost daily) and lasted less. However, this method did not find widespread use due to ignorance of the exact laws of satellite motion and the complexity of observations - the telescope that Galileo advocated was useless on a swaying deck.

In 1674, a certain Henry Bond proposed another way to determine longitude - by comparing the observed magnetic declination and its value plotted on the map. (According to some sources, the idea of ​​​​determining longitude by magnetic declination was expressed earlier, for example, in 1599 by E. Wright from Cambridge in the essay “Some Errors in Navigation, Discovered and Corrected.”) To implement this method, a publication was published in 1702 map of the world with lines of equal declinations marked on it. However, this method was of little help to sailors: isogon lines (equal declinations) are not always located favorably for determining longitude, i.e. from north to south, they often run along a parallel and are very sparse. In addition, the declinations known at that time were measured roughly and only in certain areas, and the variability of the declination was still little studied. So this method could only determine longitude approximately and not everywhere.

The first to suggest using a clock to determine longitude at sea was the Frisian astronomer and mathematician Gemma Frisius. In 1530, in his work “Principles of Astronomical Cosmography,” he wrote: “In our century we have a number of small, skillfully made clocks that find a certain use. Due to its small size, these watches are easy to travel with. They can often go on continuously for over 24 hours. And with your help they can go forever. Using such a clock and some methods, longitude can be determined. Before we set out on a journey, we must take care to find the exact time at the starting point from which we depart. When we have gone 15-20 miles, perhaps we can find out the difference in longitude between the place we have reached and the place of our departure. We must wait until the hour hand of our watch approaches exactly the hour mark of the dial, and at the same moment, using an astrolabe or globe, determine the time in the place where we are. If this time coincides to the minute with the time shown by our watches, then we can be sure that we are still on the same meridian, or at the same longitude, and our journey took place in a southerly direction. But if this difference reaches one hour or a certain number of minutes, then we must convert these values ​​into degrees or degree minutes... and thus obtain longitude.” But in order to “carry” the local time of the departure port with you, you needed a very accurate watch that could work for a long time in conditions of pitching, humidity and large temperature differences. For example, at the latitude of the equator, a clock error of just one minute led to an error in determining longitude of 15 miles, i.e. almost 28 kilometers. But there were no such watches at that time. And the positions of the celestial bodies were determined very roughly. The problem remained unresolved.

The author of one of the nautical works of that time wrote: “Currently there are some inquisitive people who would like to have a way to determine longitude, but the process of finding it is too difficult for a sailor, as it requires deep knowledge of astronomy; why I would not want anyone to think that longitude at sea can be found with the help of some instrument; Therefore, let the sailor not confuse himself with any rules that serve this purpose, but in the usual way, let him thoroughly discuss his voyage and keep a reckoning of the path of his ship.”

In 1567, the Spanish King Philip II offered a reward to anyone who could find a simple way to determine longitude at sea. In 1598, Philip III repeated the promise of reward. Large sums were offered by the States General of the Netherlands, Portugal and Venice. A number of proposals emerged. One of them fell into the hands of Huygens in 1655. He quickly realized that the proposed project was incorrect. But the question interested him, and he started designing watches. Most of all, as can be seen from the scientist’s letters, he was interested in a sea clock that would be able to keep time for many months in any climatic conditions and with any movements of the ship.

Work on the theory of the pendulum was useful: in the clock he invented, the spring created a force that drove the system of clock wheels, and the pendulum ensured the uniformity of their movement.

In 1658, Huygens published his invention and... was accused of plagiarism on the grounds that the idea of ​​a pendulum clock belonged to Galileo. Huygens carefully read Galileo's works and became convinced that they contained only an idea that had not been technically realized, and answered his opponents that he considered it a great honor for himself that he had managed to solve a question that even the great Galileo had not completed.

While working on the clock, Huygens achieved precise isochronism of the pendulum's oscillations and the creation of a support-anchor escapement, thanks to which the pendulum receives periodic shocks that prevent it from stopping due to friction and air resistance.

In 1662-1677. Huygens’ “time keepers” were tested at sea. The clocks on ships were attached to a pole and covered with a special case. Later, in order to reduce the influence of pitching, Huygens proposed hanging watches in cardan rings.

In 1668, Huygens' clock, having withstood two storms and a naval battle, made it possible to determine the difference in longitude between Toulon and Crete with an error of 100 kilometers. This was undoubted progress for that level of navigation. However, positive results often gave way to failures. Thus, in 1670, during the voyage of the Dutch admiral Richer to Canada and India, the discrepancy in longitude turned out to be very large. Huygens, having carefully analyzed the results of all tests, came to the conclusion that the pendulum, despite all the measures taken, “works” erratically in the ship’s conditions and is not reliable enough. Even a small change in the length of the pendulum, for example due to an increase (decrease) in temperature, significantly affected the accuracy of the clock. Therefore, in 1674, he abandoned it and proposed using a balancer as a speed regulator - a flywheel that, with the help of a spring, performs oscillatory movements around the equilibrium position. This was a significant step forward. But another 100 years passed before it was possible to produce a marine chronometer that satisfied the requirements of seafarers.

We owe to Geygens not only the adaptation of the pendulum to the clock, but also the development of the foundations of his theory, in particular, the determination of the formula for its movement. Published in 1673, the scientist’s book “Pendulum Clocks” is one of the most remarkable works on mechanics written in the 17th century. It is no coincidence that it was put on a par with Newton’s famous “Principia”.

The discovery of the laws of the pendulum made it possible not only to create accurate time meters, but also contributed to a number of other discoveries and inventions, V including in navigation technology.

The pendulum helped establish that the force of gravity on the earth's surface changes. It happened like this. In 1672, the French astronomer Richet, on behalf of the Paris Academy of Sciences, went to the equatorial zone of South America for observations. Arriving in Cayenne, he unexpectedly discovered that the pendulum clock, carefully calibrated in Paris, began to lag by two and a half minutes per day, that is, the pendulum began to oscillate much more slowly than usual. To restore normal speed, it had to be shortened. When Richet returned to Paris after two years of work in Cayenne, he noticed that his watch was now fast by exactly two and a half minutes. There could be only one conclusion - the force of gravity, on which acceleration depends, is weaker at the equator than in Paris.

After the publication of Richet's observations in 1679, controversy broke out among scientists. Various assumptions were made, but only Newton was able to understand the reason for the change in the clock rate. He explained that the weakening of gravity at the equator is caused by the rotation and compression of the Earth, which was not yet known to scientists. Thus, thanks to the pendulum, Newton, without leaving his office, proved that the Earth is compressed at the poles and elongated along the equator, that is, the figure of the Earth is a compressed ellipsoid. Hence the difference in attraction - the closer the body located on the surface of the Earth to its center, the greater the attraction.

Subsequent studies using a pendulum made it possible to clarify the shape of the Earth and establish the so-called “level surface”, which is taken in calculations as the surface of the Earth. The body bounded by this surface, existing only in the space of the oceans and extended under the continents, was called geoid. Unlike the earth's elliposide, the geoid does not represent a regular geometric figure. Determining the position of the geoid surface is very important for accurate navigation.

The pendulum has found particularly wide application in technical means of navigation, mainly as a sensitive element in instruments for determining the vertical, but we will talk about this later, and now we will return to the problem of longitude.

Solving the Longitudinal Problem

The end of the 17th - beginning of the 18th century. were marked by a number of major maritime disasters. In 1691, off the coast of England, several warships ran aground, mistaking Cape Dowman for Cape Berry Head in the Plymouth area. In 1694, due to an error in calculating its location in the Strait of Gibraltar, Wheeler's squadron ran aground. Her navigators made a mistake in their calculations, believing that the strait had already been passed.

The most tragic was the death of a number of ships of the English squadron of Admiral Claudisley Shovel, which claimed about 2,000 human lives, including the admiral himself. In September 1707, a squadron of 21 ships headed from the Mediterranean Sea to their native shores. On October 21, she approached the mouth of the English Channel. In the previous days, a storm raged, there was no sun, the sailors could not clarify the latitude, as a result of which they made a mistake in calculating their place and ended up on the rocks near the Isles of Scilly.

The loss of so many lives and the loss of so many ships in a short period of time agitated England. It was obvious that the disasters were associated primarily with inaccurate maps, poor-quality directions, and mainly with the inability to accurately determine one’s location. The problem of longitude became more acute; it was considered the key to ensuring safe navigation.

The issue of determining longitude became the subject of frequent debate in the English Parliament; according to its decision, a special commission was created, which included such outstanding scientists as I. Newton, E. Halley, D. Flamsteed. Parliament instructed the commission to develop a bill that would stimulate work to ensure navigation safety and provide a large reward to the person or group of people who proposed a solution to the problem of determining longitude at sea.

On June 17, 1714, the bill presented was approved by Parliament, and on August 1, 1714, signed by Queen Anne of England.

According to this law, a large prize of 10 thousand pounds sterling was promised to the author or authors who proposed a project making it possible to determine longitude with an accuracy of at least 1° or 60 nautical miles; 15 thousand pounds sterling - if accuracy of at least 40 miles is ensured; and 20 thousand - 30 miles (20 thousand pounds sterling of the 17th century is equivalent to almost half a million today). At the same time, the law on longitude made a significant reservation that the proposed method must necessarily be “tested and evaluated from the point of view of its practicality and usefulness at sea.”

Simultaneously with the adoption of the law, the commission of experts was transformed into the Council for Researching Methods for Determining Longitude at Sea. It was to include, in addition to eminent scientists, the High Admiral of Great Britain, the President of the House of Commons, the first member of the Council from the Navy, a representative from the Ministry of Commerce, the President of the Royal Society, the Astronomer Royal and ten members of Parliament.

France followed the example of England. In 1716, the regent Philippe, Duke of Orleans, established a prize for the determination of longitude, awarded by the French Academy of Sciences.

The adopted law on longitude and the awarded prizes were a good incentive to intensify work to ensure navigation safety. However, none of the proposals received by the Council before 1737 was fully approved.

One of the first applications to compete for the prize was the idea of ​​mathematicians Humphrey Ditton and William Winston, published in 1714. They proposed to anchor ships at certain distances along the busiest sea routes, measuring their geographical coordinates. Exactly at midnight local time on the island of Tenerife, each ship was supposed to fire a salvo of mortars in a vertical direction so that the shells exploded exactly at an altitude of 2000 meters. Vessels passing by had to measure the bearing of the signal and the range (based on the time between the flashes and the moment the sound signal arrived) and determine their location from them.

Regarding this fantastic proposal, as the historian of the Greenwich Observatory D. House writes, poems with such ironic content were soon published:

Sly Winston longitude
Hidden from us in the fog.
Dear Ditton with him
Guilty of that deception.
So, friends, we will repay you in full.
To the merits of these men of science,
Longitude has disappeared for us,
But stupidity asks us to take it into our hands.

The Longitude Act award, totaling £22,500, was not awarded until the mid-1970s. XVIII century eighty-year-old mechanic John Harrison, or, as he was also nicknamed, John Longitude, for the creation of high-precision chronometer watches (from the Greek “chronos” - time and “metros” - measurement), which finally made it possible to solve this problem for centuries, associated with unsolvable “squaring of the circle”.

And it started like this. John Harrison, the son of a rural carpenter from Wakefield in Yorkshire, was interested in watches in his youth and achieved good results in this - the designs of the watches he created were distinguished by accurate and stable movement. In 1730, while in London, he first learned about the prize appointed by Parliament and that one of the ways to solve the longitude problem lay in the creation of an accurate “time keeper.” The task seemed within his capabilities, and he set to work.

Harrison began by solving the questions that had already arisen before Huygens: it was necessary to reduce to a minimum the dependence of the clock on changes in temperature, humidity, pitching and the progress of the ship. Back in 1725, to ensure temperature compensation, he developed a pendulum assembled from zinc and steel rods, that is, from dissimilar metals with different expansion coefficients. The rods were connected in such a way that when the temperature changed, the length of some increased and the length of others decreased. With proper selection of rod sizes, the length of the pendulum remained unchanged during temperature fluctuations. This technical solution gave excellent results, and now he decided to implement it in a new watch in the form of a composite balancer. He made his wheel not solid, like Huygens's, but consisting of two soldered strips, one of which was made of brass, and the other of steel. This made it possible to ensure the chronometer's resistance to temperature fluctuations.

Harrison completed the first chronometer in 1735 and presented it to the Board of Longitude. Its design was very unusual. The pendulum was replaced by two large balance wheels, which swung in opposite directions, as a result of which the influence of the ship's movement on one balance wheel was compensated by the other. The balancers themselves, as we have already mentioned, were composite. To indicate the time, four dials were provided - for seconds, minutes, hours and days. The chronometer was very bulky and weighed more than 30 kilograms, although many of its parts were made of wood.

In 1736, with the assistance of E. Halley and the direct participation of the inventor, tests of this chronometer were carried out on the ships “Centurion” and “Orford”. The device showed good accuracy, which was confirmed in writing by the ship captains. However, neither Harrison himself nor the members of the Council were fully satisfied with the results, since the ships made a voyage to Lisbon and back, that is, along the meridian, and with such a voyage it was difficult to assess the accuracy of maintaining the initial longitude.

In 1739, the second sample of the chronometer was made. But it differed little from the first - it was bulky and heavy, like its predecessor (height about 1.5 meters, and weight almost 50 kilograms). The work did not satisfy Harrison, but it gave rise to a number of new ideas, and he began manufacturing the third version of the chronometer, which took 19 years. The Council decided to test the new chronometer under the difficult conditions of a long voyage to the West Indies. While preparations for the campaign were underway, Harrison presented a fourth option, which, in his words, “exceeded all expectations.”

On November 18, 1761, the ship “Deptford” with chronometers, which was accompanied by John’s son William, headed for Jamaica. Over 81 days of sailing, the watch accumulated an error of only 5 seconds. They also showed fairly high accuracy on the way back to England - the error in the coordinates upon arrival in Portsmouth was only 16 miles.

Thus, the conditions of the law of 1714 were fulfilled and Harrison had the right to count on the long-awaited prize. However, the Council of Longitude decided to limit itself to a reward of 5,000 pounds sterling for now, citing a lack of data and the uniqueness of the one-off sample. Harrison refused this money, wanting to get all 20 thousand and insisted on repeating the tests under even more stringent conditions. They were carried out in 1784 during the voyage of His Majesty's ship Tartar from Portsmouth to the island of Barbados. The strictest measures were taken to ensure the impartiality of the tests and the objective assessment of their results. And this time they were great. To make a final decision on the prize, the Council demanded that the secrets of making the chronometer be revealed and, in order to ensure that it could be repeated, it instructed watchmaker Lerkum Kendall to make a copy of it.

This model of Kendall and three others made by J. Arnold, on the recommendation of the Council, were taken on his second voyage by Captain J. Cook. During the three-year voyage, the chronometer made by Kendall proved to be excellent. Cook wrote on this occasion to the Secretary of the Admiralty: “Mr. Kendall's watch exceeded the expectations of even its most zealous defenders; this instrument, whose readings were corrected according to lunar observations, was our faithful guide through all the vicissitudes and climates.”

The problem of longitude was thus finally solved. The Longitude Council's doubts were dispelled and J. Garrison received his well-deserved bonus.

In France, many people worked on creating an accurate “time keeper,” but the royal watchmaker Pierre le Roy (1717-1785) and Ferdinand Berthoud (1729-1807) were the most successful in this. Their chronometers, after many modifications, finally successfully passed long-term ship tests and showed positive results. In 1773, Pierre le Roy was awarded the royal prize for the best French chronometers.

The advantages of chronometers, or, as they were also called, “longitudinal clocks,” were quickly appreciated by sailors, but they were introduced on ships slowly, since only highly qualified mechanics could make them, and even then in small quantities. And they were very expensive. Nevertheless, all major voyages of the second half of the 18th century. were already performed with chronometers. They were used by J. Cook, J. La Perouse, D. Entrecasteaux. However, the French hydrographer Joseph de Corguelin, who on January 16, 1772 set off from Port Louis on the island of Mauritius in search of the Southern Continent, was unable to obtain the chronometer, despite great efforts. This led to the fact that the location of the archipelago he discovered, which was later named after him, was determined with an error of 240 miles, i.e. approximately 450 kilometers.

Mass production of chronometers for navigation was mastered in Western European countries only towards the end of the 18th and beginning of the 19th centuries.

In Russia, the need for accurate time measurement to determine a place at sea was understood early. Even M.V. Lomonosov believed that the best way to determine longitude is to compare “the time on the ship meridian and the time on the first meridian.” While dealing with the preparation of a special expedition to open the shortest sea route from Europe to China, he not only made a number of improvements to watches to make them more suitable for use on a ship, but also proposed his design of a four-spring sea watch, which, according to the author’s plan, should , ensure uniform movement and the ability to start them without stopping. Lomonosov drew attention to the fact that the movement of the sea clock is significantly influenced by changes in the ambient air temperature and the dynamics of the ship, and during the expedition he recommended: “Put the clock inside the ship, in the part immersed in the sea, where the dissolution of air changes little. Moreover, this position in the middle of the ship is not subject to so many fluctuations.”

To avoid the influence of temperature fluctuations and pitching, the scientist also proposed using “metal pour clocks”, similar to sand clocks, but filled with silver shot specially made using his technology. According to Lomonosov, such a watch should have made it possible to “make astronomical observations on the ship’s meridian” and, by comparing its readings with the time on the first meridian, it would be possible to “derive the longitude of a place.”

Of course, such a watch could not compete with a chronometer, but it is important to emphasize the aspiration in this direction of thought of the scientist, who at that time was not yet familiar with Garrison’s work.

Watchmaking in Russia at that time was well developed. It is enough to recall such outstanding masters as the mechanic of the Russian Academy of Sciences I. P. Kulibin (1735-1818), his contemporary T. I. Voloskov (1729-1806), L. F. Sobakin (1746-1818) and others. Sobakin created astronomical clock, which had no equal in its complexity. They showed not only time in hours, minutes and seconds, but also reproduced the movement of the Earth around the Sun and the Moon around the Earth and the change in their position relative to the fixed stars; the movement of the Sun along the ecliptic with the designation of the 12 signs of the zodiac, sunrise and sunset in different places; alternation of leap and non-leap years; changes in the phases of the Moon, lunar eclipses; geographical coordinates of the most important cities; “perpetual” calendar indicating the current month and the number of days in it; numbers and names of the day; information on political geography, etc.

But it was, of course, a large wall clock. Russian craftsmen did not produce marine chronometers at that time, and they were purchased from foreign companies, mainly from English ones. Six chronometers were installed on the sloops “Nadezhda” and “Neva”, which made voyages in 1803-1806. circumnavigation of the world under the command of I. F. Krusenstern and Yu. F. Lisyansky. Using chronometers, F.F. Bellingshausen and M.P. Lazarev determined longitude during an expedition to Antarctica in 1820 on the sloops “Vostok” and “Mirny”. Thus, in his diary, M.P. Lazarev noted: “We were in Tahiti to check our chronometers, which turned out to be correct, and therefore we can conclude that our discoveries were put on maps with fairly accuracy.”

In 1839, the Pulkovo Observatory was founded, the purpose of which, according to the charter, was to produce: “a) constant and as perfect observations as possible, tending towards the success of astronomy, and b) relevant observations necessary for geographical enterprises in the empire and for scientific travel. Moreover, c) it must contribute by all means to the improvement of practical astronomy...”.

The founding of the observatory contributed to the development in Russia of work on precise time keepers.” In particular, in 1856, in “Marine Collection” No. 2, the work of the director of the Pulkovo Observatory, Academician V. Ya. Struve, “On compensation of chronometers” was published, in which he developed recommendations for adjusting chronometer readings taking into account changes in their course depending on changes temperature. This made it possible to increase the accuracy of determining longitude.

Chronometers purchased from foreign companies were carefully checked at the Kronstadt Naval Observatory, established in 1856, and then sent to ships. Here they also conducted research on the constancy of their course, sensitivity to changes in temperature, humidity, etc. The duties of the astronomer of the Kronstadt Observatory included “accurate determination of time for both military and merchant ships, checking chronometers and showing time to ships in the roadstead.” and in the harbor... carrying out scientific research regarding the application of astronomy to navigation.”

In 1849, at the Exhibition of Russian Manufactured Products, a marine chronometer made by the Russian master A.F. Rogin was already presented as an exhibit. Since 1865, the workshop of August Erikson, located in St. Petersburg, began producing chronometers. The products of this workshop were highly appreciated at a number of industrial exhibitions and among sailors. They have almost replaced chronometers bought abroad. This workshop served the needs of the navy until 1902, when the second workshop of Karl Erikson, Augustus's namesake, appeared. Dependence on imports was reduced to a minimum with the opening of this workshop.

The marine chronometer mechanism, mounted in a metal case with a glass lid, is installed in a gimbal suspension in a wooden box with a double lid. The first is opened when you just need to take the time countdown, the second - when you need to start the device and set its hands.

The constancy of the daily cycle of modern chronometers has been brought to tenths of a second. Thus, the electronic chronometer Chronostat IV, created by the Swiss company Bernard Golar S.A.), has a battery with a capacity of 18 months of continuous operation, a waterproof and shock-resistant case. The accuracy provided by the quartz crystal oscillator under unstable environmental conditions is only 0.1 seconds per day. The device can control the operation of clock repeaters located in various areas of the ship.

Now everyone is well aware that longitude is measured from the prime meridian, passing through the Greenwich Observatory near London. But it was not always so. Astronomers of antiquity measured longitude, as a rule, from the area where they made observations. For example, Hipparchus took the Rhodes meridian as his starting point, i.e. the longitude of the island of Rhodes, where he lived. His follower Ptolemy considered the meridian of the island of Fortune, which was called the western border of the world, to be zero, and the Arabs counted longitude from

Cape Verde Islands / Many sailors for a long time measured longitude in dead reckoning from the port from which the ship sailed, or from some distinctive geographical point, such as an island, cape, etc.

In 1493, Pope Alexander VI approved a line of demarcation dividing the spheres of influence of Spain and Portugal. It passed 100 leagues west of the Azores and was used by many cartographers as a zero
meridian. In the work “Arte de Navigar” (“The Art of Navigation”), created in 1556, its author Martin Cortes proposed that longitude should be counted from a vertical line drawn “through the Azores or closer to Spain, where there is more on the map
free space."
At first, such discrepancies in the choice of the prime meridian did not particularly bother anyone, but when relatively accurate nautical charts appeared, arbitrary calculation of longitude often began to lead to confusion. Each map publisher placed the meridian where he liked it best. Moreover, on some maps the longitude was measured to the west, on others - to the east. The need to put things in order in this matter became more acute during the era of the Great Geographical Discoveries, when new lands had to be plotted on maps and their geographical coordinates had to be clarified.

In 1573, King Philip II of Spain issued a decree that all Spanish maps must show longitudes from the meridian of the city of Toledo to the west.

The first attempt to establish a common prime meridian for all states was made in 1634 at a conference of leading mathematicians and astronomers convened in France on the initiative of Cardinal Richelieu. Scientists agreed to consider the meridian passing through the western coast of the westernmost of the Canary Islands - Ferro - as zero. But at that time the Thirty Years' War was going on, and the decisions of the conference were not disseminated.

In 1676, the Royal Observatory began its work, built on a high hill on the site of the old castle in Greenwich. This observatory was destined to become the most useful for navigation. It was established by order of King Charles II with the aim of “meeting the needs of seafarers.” The observatory's first major success was Flamsteed's proof that the Earth rotated at a fairly constant speed, which was very important for determining longitude using chronometers. Much was done already in the first years to organize an accurate time service in Greenwich.

The Greenwich Observatory became famous and sailors, when determining longitude, increasingly began to focus on the Greenwich meridian, especially since many of the maps and nautical almanacs used by sailors were of British origin. By 1871, twelve countries already measured longitudes on their nautical charts from the Greenwich meridian.

In October 1884, the International Meridian Conference was held in Washington “...to discuss and, if possible, to fix a meridian suitable for use as the zero of longitude and standard time throughout the globe.” The conference lasted a month. It was noted that previously put forward proposals for the passage of the prime meridian through the islands of Ferro and Tenerife, through one of the temples of Jerusalem, the Pyramid of Cheops, cannot be accepted. The requirements are such that the meridian should pass through one of the most outstanding observatories, capable of constantly making the most accurate observations, and there should not be a need for major alteration of already published maps and manuals.

Most of all, these requirements were met by the Greenwich meridian, more precisely the meridian passing through the axis of one of the telescopes of the Greenwich Observatory. The Conference Resolution stated: “From this meridian, longitude should be measured in two directions up to 180° - to the east with a plus sign and to the west with a minus sign.”

Radio time signals over the ocean

The International Meridian Conference of 1884, along with the resolution on the prime meridian, decided to use Greenwich Mean Time as universal time. It was recommended that all almanacs and nautical yearbooks be published based on local Greenwich time.

In order to accurately determine longitude, the chronometer must be set to Greenwich time and its progress must be constantly monitored. At the first stage, this problem was solved either by astronomical observations, or by comparison with a standard clock showing Greenwich time at the point of departure of the ship.

To compare chronometers with the reference “keepers of universal time,” they used portable watches, since it was not recommended to move the chronometer again, so as not to expose it to shaking and environmental changes. To display portable watches at the dawn of the appearance of chronometers, they used signals sent from the shore specifically for ships in the harbor. The signals used were turning off the searchlights, lowering the flag, firing a cannon, striking a bell, etc.

In 1824, the captain of the British navy, R. Washop, proposed using signal ball . In 1833, such a signaling device was built on the east tower of the Royal Observatory in Greenwich.

A red ball rose above the tower every day at 12:58 p.m., which served as a warning that the time was ready to be checked. Exactly at 13:00 according to the reference clock, an observatory employee freed the ball from its support, and it fell. Since 1852, the moment the ball fell was controlled using an electrical signal. The Greenwich signal ball was clearly visible to ships on the Thames.

With the introduction of the telegraph the task became easier. Now the electrical impulse sent by the reference clock could activate a signal device, a cannon, a bell, etc., anywhere, even at a great distance from the observatory. In the second half of the 19th century. Precise time signaling devices operated by telegraph were installed in many major seaports in Europe.

In St. Petersburg, back in 1735, the astronomer academician J. N. Delisle (1688-1768) proposed to synchronize the clocks every day at exactly noon, upon a signal from the astronomical observatory, to fire a cannon from one of the bastions of the Admiralty. However, this project was not approved by Empress Anna Ioannovna (1693-1740) and was forgotten for a long time.

The idea of ​​marking noon with a cannon shot was returned only in the middle of the 19th century. In 1862, a telegraph connection was established between the Pulkovo Observatory and St. Petersburg, through which precise time signals began to be transmitted. Based on these signals, it was decided to “announce noon to St. Petersburg” by firing a cannon from the territory of the Admiralty.

The signal was sent to an electric clock located in the fortress commandant's room. The latter were connected by an electric wire to one of the guns and every day at noon, by closing the contact of the electrical circuit, the gunpowder in it was ignited.

In 1905, the commander of the seaport of St. Petersburg stated that signal shots allow checking ship's chronometers only with an accuracy of 1.5 seconds, which is not enough for navigation purposes. Since then, the signals were sent only for civilian needs, and then were completely stopped. Currently, shots from the Peter and Paul Fortress are just a tribute to tradition. They were resumed in June 1957 during the celebrations of the 250th anniversary of Leningrad.

In 1866, the largest ship in the world at that time, the Great Eastern, was laying a transatlantic telegraph cable. During this work, a newly laid cable on the Great Eastern received a time signal from Greenwich by telegraph twice a day, which for the first time in the world made it possible, without visual observation methods, to determine with high accuracy the longitude of a ship’s location on the high seas.

But all ships, of course, could not carry cables with them, therefore, in order to increase the accuracy of observations and protect themselves from trouble in case of loss of time due to the clock stopping, the navigators carried several chronometers with them and used the average value of their readings. The same method was used to increase the accuracy of determining the longitude of various geographical points. Thus, in 1823, when determining the difference in longitude between Dover and Portsmouth, 30 chronometers were transported by sea. When taking the coordinates of the Baltic Sea in 1833, the expedition of the Russian geographer F. F. Schubert used 56 chronometers, and when determining the coordinates of the Pulkovo Observatory, 81 chronometers were already needed.

On May 7, 1895, the Russian scientist and electrical engineer A. S. Popov (1859-1905/06) demonstrated at a meeting of the physics department of the Russian Physical-Chemical Society the radio receiver he had invented for the first time in the world. Electrical communication without wires was born. In March 1896, the world's first two-word radiogram, “Heinrich Hertz,” was transmitted over a distance of 250 meters. In the spring of 1897, the radio communication range reached 600 meters, and in 1901 - already 150 kilometers.

The invention of radio radically changed the entire time service, including on ships.

The Americans were the first to take advantage of the opportunity to transmit time signals by radio for navigation needs. In 1904, such signals began to be transmitted by the US Navy radio service from the state of Navesinka. In January 1905, the Washington radio station began regular transmissions of midday time signals, and in 1907, the Norddeutsch Radio radio station in Germany.

In 1908, the French Bureau of Longitude decided to transmit radio time signals from the Eiffel Tower. Regular broadcasts began on May 23, 1910 at midnight. The signal pendulum of the Paris Observatory, when swinging, closed a contact in the electrical circuit and, via a cable, activated the relay of the emitting radio station installed on the Eiffel Tower. The rhythmic signals of this radio station made it possible to determine errors in the timing of chronometers with an accuracy of 0.01 seconds. Since 1912, the Greenwich Observatory also began transmitting time signals.

Keeping time has become much easier. Sailors could now check their chronometers without entering a port. In addition, there was no need to create particularly accurate ship chronometers capable of storing Greenwich time for a long time and without checks.

Every year the number of radio stations transmitting time signals grew. Moreover, each set its own signal transmission time and code. There was a need to somehow streamline this work, and in October 1912, on the initiative of the French Bureau of Longitudes, a conference of 16 European and American countries on the issue of radiotelegraph time transmission met in Paris. Three delegates from Russia also took part in the conference: the director of the Pulkovo Observatory, academician O. A. Backlund, the Minister of Trade and Industry, mechanic of the Main Chamber of Weights and Measures F. I. Blyumbach, and from the Maritime Ministry, the acting assistant to the head of the Main Hydrographic Directorate, Captain 1- rank A. M. Bukhteev.

The conference approved, from July 1, 1913, a unified system of time signals “Onogo” for radio stations in all countries, and also recommended such a schedule of radio stations so that they do not interfere with each other. A schedule was also provided for those radio stations that may appear in the future. It was assumed that at least one time signal per day could be received everywhere on the earth's surface, except for the polar regions. The need to transmit, in addition to ordinary signals for general use, and special signals for “scientific purposes” was noted.

Radio not only made it possible to send on the air a time signal of the reference clocks of specific observatories, but also opened up the opportunity to “unite” the time produced by them, i.e., to create a Unified International System for generating accurate time, which made it possible to eliminate the discrepancy between the times of different observatories.

To implement this idea, the conference elected a special “preliminary” International Time Commission under the leadership of the Director of the Pulkovo Observatory, Academician O. A. Backlund. This commission developed a project for the creation of an International Time Bureau and sent out proposals to the governments of different countries to join the international time service to organize the transmission of high-precision united time to the entire globe. However, the First World War suspended this work.

This issue was returned to in 1919 at a conference in Brussels, where the International Astronomical Union was created. At the congress of this union in the same year, a permanent International Time Bureau was established, whose task was to coordinate and summarize the work of all time services in the world.

In Russia, regular reception of radio time signals began in May 1913. Already in 1914, an attempt was made to clarify the longitude of the Pulkovo Observatory using radio time signals. In 1920, the astronomical observatory in Pulkovo began regularly transmitting accurate time signals. Signals were transmitted daily, first at 19:30, and from July 1921 at 19:00 universal time through the Petrograd radio station “New Holland”. On May 25, 1921, signals began to be transmitted through the Moscow October Radio Station on Khodynka.

It should be noted that the authors of the radio signals “New Holland” and “Khodynka” did not adopt the international “Onogo” system, but for some reason invented their own, which was strongly opposed by the famous Soviet hydrograph-geodesist N. N. Matusevich (1875-1950). In 1923, he published an article in “Notes on Hydrography” in which he showed the inconvenience of the new system for navigators and its shortcomings in comparison with the international one and proposed switching to the “Onogo” system.

During this period, marine astronomical observatories in Kronstadt, Nikolaev, Sevastopol, Vladivostok and Akhangelsk also began to play a major role in serving time for navigation purposes. Their job was to determine the corrections of the standard clocks and to determine the daily astronomical half-day.

In 1948, an Interdepartmental Commission of a Unified Time Service was established in our country under the State Committee of Standards of the Council of Ministers, the main tasks of which were to resolve issues related to the transmission of precise time signals and coordinate work in this area of ​​various interested departments.

Currently, information about the standard time is transmitted through radio stations and television by the State Time and Frequency Service (STSF), which combines the activities of astronomical observations, reception and transmission of time signals from 21 observatories, including foreign ones. Information about domestic and foreign radio stations transmitting time signals, as well as their broadcast programs, is published in the bulletin “Reference Frequency and Time Signals”, published by the Interdepartmental Commission of the Unified Time Service under the State Committee of Standards of the Council of Ministers.

The deviation of the exact time signals transmitted by domestic leading radio stations from the scale of the State Time and Frequency Standard does not exceed 0.00003 seconds. The country's broadcasting stations broadcast time check signals in the form of six second pulses at the end of each hour. The last sixth signal corresponds to 00:00 from the next hour.

The accuracy of production and storage of reference time in observatories has also changed radically. At the time of the founding of the Greenwich Observatory, the exact time stamp was obtained using special astronomical observations. This was done with a passage instrument - a telescope, installed strictly along the meridian. Determination of moments in time was carried out by observing the passage of the image of stars through the eyepiece thread. The more accurately the astronomer notes the moment the star passes through the eyepiece thread, i.e., through the meridian of the observer, the more accurately the correction of the astronomical clock and, therefore, the more accurately the local time can be determined. The accuracy of determining moments by this method was several tenths of a second. It was possible to increase the accuracy several times by using automatic recorders of the passage of a star in the field of the telescope eyepiece, in particular photoelectric devices, chronographs, photographic zenith tubes and other means and methods.

Time was kept in observatories between astronomical observations using mechanical pendulum clocks and chronometers. To ensure high accuracy, such watches were placed in deep basements, where it was easier to ensure constant temperature and atmospheric pressure and protect the instruments from possible shocks. Currently, to obtain moments in time, atomic standards are used, which reproduce the duration of a second of ephemeris, i.e., mathematically uniform time, with an error of no more than 10~ 12 -10~ 13 seconds.

The atomic clock is based on the oscillatory processes of atoms of chemical elements, in particular cesium atoms, which occur with exceptional constancy.

Such high accuracy of time standardization and broadcasting is needed primarily for scientific and special purposes (space navigation, radio navigation, communications, etc.). For marine celestial navigation, the requirements are significantly lower. Thus, for celestial navigation measurements, it is enough to know the universal time with an accuracy of hundredths to tenths of a second. For daily activities, the ship's marine clock should not differ from the exact time by more than 0.25 minutes.

To provide accurate time for navigation and astronomical determinations, organize watch service and solve other problems on modern ships and vessels, a special time service has been created. Its functions include:

- ensuring accurate universal time storage;

- receiving precise time radio signals and calculating corrections for chronometers and marine clocks;

- monitoring the work of “time keepers” and servicing them;

- distribution of information about the exact time to various posts, etc.

The chronometer is always stored in the same place - in a special compartment of the chart table. It cannot be moved, except for repairs or in case of demagnetization on the ship (under the influence of electromagnetic fields, the daily course of the chronometer can change significantly). The place where the chronometer is stored must be removed from sources of magnetic and electromagnetic fields, mechanical installations that cause vibration, and thermal lines that lead to sudden temperature fluctuations.

To set the chronometer according to universal time, the hand readings are set in advance for the nearest Greenwich time of radio signals. At the moment the signal is received, the chronometer is started by rotating it around the vertical axis by 40-45°. After this, the accuracy of the time is examined and corrections are determined by comparison with another time standard or by radio signals transmitted in subsequent hours.

If particularly high accuracy is required, then the standard seconds signals are received several times in a row, recording the chronometer readings, and the average value is calculated. The maximum error in determining the chronometer correction when receiving signals auditorily is from 0.2 to 0.5 seconds.

To record time during astronomical observations, the so-called deck clock is used, which is a portable clock with a second hand moving in 0.2-second increments, or a stopwatch. During observations, the clocks are set to universal time using a chronometer using the comparison method. A stopwatch is used to measure short periods of time.

At the moment of measuring the heights of the luminaries, the time is recorded and then, taking into account the appropriate corrections, the Greenwich time of observation is calculated.

Many ships and vessels are currently installed with an electronic ship time system (SVEC).

The system consists of functionally and structurally complete modules that allow the formation of various configurations depending on the requirements of ships and vessels.

The basis of the system is a quartz chronometer KH, providing time storage with an error of no worse than one second per 40 days. Such accuracy was achieved due to the properties of the piezoquartz plate, when an electric current is applied to it, to perform periodic oscillations with an extremely constant frequency and low attenuation. Elastic oscillations of the quartz crystal replaced the oscillations of the pendulum. A quartz chronometer uses a small frequency oscillator stabilized by quartz. The generated oscillations are converted by an electronic circuit into signals that control the movement of clock hands or digital displays.

Quartz watches are less affected by temperature, humidity, pressure, etc. than mechanical chronometers.

The coded time signal generated by the quartz chronometer is sent to the clock station SChS with a dial indicator and a digital clock station SCC with digital time indicators. SChS converts the time code coming from the chronometer into a sequence of pulses controlled through repeaters R operation of the electronic secondary clock EHF, which can be placed at various ship posts at a distance of up to 500 meters from SChS.

Total k SChS Up to 100 dial clocks can be connected. If used up to 10 hours, they can be directly connected to the chronometer without repeaters.

SCC converts the time code received at its input into a parallel binary decimal code, which controls the operation of four secondary digital clocks PVC. Digital displays display information about the current time in hours, minutes, seconds and tenths of a second. Instead of just a digital clock, the exact time code can be issued to a digital computer TsVM, solving problems related to precise time.

On PVC It is possible to record the current time using the button on the front panel and the remote control of the clock and, if necessary, turn off and on the tenths of a second indicators without losing chronometric information.

The modular design of the time system allows you to install on a ship SVEC only with dial indicators or only with digital indicators or with both.

In the event of loss of power from the mains, the system automatically switches to batteries. To automatically link SVEC to time signals, a radio correction unit is used DBK. The accuracy of automatic binding is no worse than 0.03 seconds. The alignment can also be done manually, that is, when receiving signals by ear. The binding error in this option should not exceed 0.3 seconds.

The introduction of SVEC increases the accuracy of time storage and significantly facilitates the solution of celestial navigation problems.

The daily activities of ships and vessels are organized according to ship time, which can correspond to standard time in the navigation area, as well as Moscow or world time, depending on the tasks being solved. The ship's marine clock and the secondary SVEC clock are set at this time.

On the basis of the First Moscow Watch Factory "Polyot" in modern Russia, the unique production of marine precision time instruments has been preserved, in which every detail is made by watchmakers within the walls of the Moscow manufactory.

The 6MX watch manufactory has been producing marine chronometers and deck watches since 1947. Chronometers under the “Polyot” trademark are equipped with almost all vessels without exception that are on watch in the seas and oceans. High accuracy and impeccable workmanship allowed them to be included in the Lloyd's Register as marine precision time instruments serving navigational safety.

Since 2016, the company has been producing chronometers and deck clocks not only for military and civilian ships, but also for collectors. A new project of the watch manufactory is the creation of a wrist chronometer, a watch with the most accurate movement. Russian and German watch engineers are working together on the project, combining the experience of producing parts and watch movements of the highest quality.

Simultaneously with the release of high-precision wristwatches with in-house movements, a rebranding was carried out. Now the products are produced under the trademark “6MX” (previously produced under the trademark “Polyot”), which is understandable to marine specialists and arouses the interest of the buyer with an unusual abbreviation.

Today, the products of the 6MX watch manufactory include:

* marine chronometer "6MX"— a marine precision time instrument (with a daily accuracy of +/- 0.5 seconds). It is operated permanently in the chart room of ships, and is also a subject of interest to collectors. Available in two configurations:

— “Prestige” — with a gold-plated case. The gimbal and all decorative elements of the storage and transportation cases are also gilded. The cases are made of polished valuable wood.

— “Private” — in a brass body. This configuration is supplied to ships.

* deck clock "6MX"— a marine precision time instrument (with a daily accuracy of +/- 6 seconds). It is a spare chronometer on the ship, which can be removed from the chart room.

Currently they are produced in cases coated with gold or rhodium. For collectors they are produced with an openwork mechanism, inlay and other decorative designs.

* wrist chronometer “6MX”— wristwatches with high precision (+/- 6 seconds per day). The first Russian wristwatch with chronometric precision. Developed and assembled together with German watch engineer Rolf Lang. Every detail of the watch is made by hand. Produced in limited quantities. Possible production in cases made of precious metals.

* wristwatch “6MX”— watches with quartz movement. The collection is available in three colors. “6MX” wristwatches are premium products for ship captains and are of interest to buyers and collectors.

The manufactory's services include personalization of purchased watches.

The best watchmaking traditions and high skill of watchmakers are the key to the quality of the 6MX manufactory’s products.

Materials used from the official website and official page of the Watch Manufactory

We talk about how marine chronometers helped create empires

Determining coordinates at sea has long been the most important of the arts. If captains learned to determine the latitude of a ship’s location by the stars and the height of the pole above the horizon back in the 15th century, then the search for an accurate method for determining longitude stretched over the next three centuries. And these searches were reminiscent of the creation of an atomic bomb: whoever gets ahead of others will become the strongest.

After all, the era of great geographical discoveries had just ended, and the leading European powers wanted to stake out the open lands for themselves at all costs. Trade and shipping in those days expanded faster than industry: why produce something when you can simply loot, bring and sell for fabulous profits.

The most delicious colonies were in the west and east, and when traveling there, knowledge of longitude was extremely necessary. Many ships died before reaching just a few miles from their desired destination, as fear and the threat of mutiny on the ship forced the captains to turn back. Even more crashed against the coastal rocks during storms and fogs.

As a result, in 1714, the English Parliament announced an international competition to create an instrument or method for determining longitude with an error of 20 or 30 miles during a voyage to the West Indies and back.

Prizes of 10, 15, 20 thousand pounds sterling (colossal money at that time) were also awarded, depending on the accuracy of determining longitude. To adopt and consider proposals for this law, the Bureau of Longitude was created, headed by the father of physics himself, Isaac Newton.

Sir Isaac Newton

From the very beginning, two methods of determining longitude emerged: astronomical and mechanical, using a clock.

Astronomy was championed by Galileo Galilei, who created a generally good method for determining the longitude from the eclipse periods of the four satellites of Saturn he discovered. However, it was sometimes not possible to do this even in Italy, where clouds are rare guests.

What can we say about the sea: first try, during a slight rocking motion, to at least catch Saturn in a telescope, not to mention its satellites. As for the mechanical method, after several attempts to imagine a marine clock, Newton, having studied them, wrote in 1714:

Using an accurate clock you can determine longitude. But since the ship is in constant motion, experiences changes in heat and cold, exposure to humid and dry air, and the force of gravity changes at different latitudes, such a watch is not yet possible to create, and it is unlikely that this will ever happen in the future.

And yet, the unheard of reward forced the best minds of that time to tense up, and in 1735, the British master John Harrison (1693-1766) created the great marine chronometer H1 “Grasshopper”.

The creator of marine chronometers is John Harrison. Photo: http://www.rmg.co.uk

The role of the pendulum in it was performed by two long balance levers with balls at both ends. Connected to each other in the middle, they formed the letter X with sticks oscillating in opposite directions, which thereby neutralized the effect of pitching. The levers were driven by four balance springs. Temperature differences were compensated by brass and steel rods to which the ends of the springs were attached.

John Harrison's first marine chronometer H1 (“Grasshopper”), 1735. Photo: http://collections.rmg.co.uk

During the test trip to Lisbon and back, the “Grasshopper” earned very positive reviews, and a message about Harrison’s invention appeared in the reports of the Greenwich Observatory. However, all this did not convince Parliament to give Harrison the required bonus; he only received a grant for the creation of new chronometers.

There is a story that John Harrison was not particularly worried about the fact that he was not awarded the prize for the invention of the “Grasshopper”, since his chronometer was secretly acquired by pirates who paid him more than the required amount

The master improved his chronometer all his life. The second chronometer H2 differed from the first in a device for stabilizing the impulse with intermediate springs.

In it, two coil springs were wound up every half hour, and the torque was always at the same level. Also in the mechanism there was a fusee as a constant force module. They did not test the H2 because there was a war with Spain, and the Admiralty feared that the formidable strategic weapon - the chronometer - would fall into the hands of the enemy.

If the first “Grasshopper” is kept at the Greenwich Observatory, then the fate of H2 and H3 is not so known (although the structure of their mechanisms is described in great detail). I think there were pirates here too.

John Harrison's marine chronometers - H2 and H3. Photo: http://collections.rmg.co.uk

And Harrison still received his prize of 20 thousand pounds in 1759, for the H4 chronometer, which was already similar to the marine chronometers we know - a kind of tabletop or very large pocket watch.

John Harrison's first marine chronometer H1 (“Grasshopper”) 1735. together with the award-winning chronometer H4 from 1759. (in the center). Photo: http://www.e-reading.club/chapter.php/103039/23/Hauz_-_Grinvichskoe_vremya_i_otkrytie_dolgoty.html, http://collections.rmg.co.uk

The mechanism was housed in two silver cases with a diameter of 10.5 cm. The dial was covered with white enamel; On this white background there were decorations made in black. The steel hour and minute hands are painted blue; there was also a central seconds hand that rotated between two other hands. The watch was wound through a hole in the back of the inner case.

John Harrison H4 Marine Chronometer. Photo: http://collections.rmg.co.uk

Harrison's sea clock No. 4, unlike his first three sea clocks, was not suspended from a gimbal, but when the ship was rolling, it was placed on a soft cushion, and by means of an outer case and a graduated arc, its position could be adjusted so that it was slightly inclined to horizontal.

The master's son William tested them on a trip to Jamaica. The Deptford sailed from Portsmouth on November 18, 1761, and when it arrived at Port Royal 61 days later, H4 was only 9 seconds behind!

Having acquired an accurate clock, the captains of the Royal Navy gained a colossal advantage over the ships of other powers, and it was thanks to the clock that the great British Empire soon arose, on which the Sun never set.

If the Spaniards, French and Dutch were forced to stock up on dozens of barrels of fresh water and food just in case, then the British, having accurate information about longitude, instead of food “rigging” stocked up with extra barrels of gunpowder, cannons and cannonballs, which, as a rule, decided the outcome of battles in their favor.

But the most important merit of John Harrison is that he instilled confidence in other best masters: Larkum Kendall, Thomas Muge, John Arnold, Pierre Leroy, Ferdinand Berthoud, Abraham-Louis Breguet. With the invention of the anchor escapement, chronometers became even more accurate, and Ulysses Nardin gained fame as the largest manufacturer.

Marine chronometers were supplied to the German Navy by A. Lange & Söhne from Glashütte. And when all the equipment, along with technical documentation, was expropriated and taken to the Soviet Union, soon Soviet ships began to receive Poljot marine chronometers with a mechanism that was an exact copy of the ALS 48 caliber.

And now, when the ship’s coordinates are automatically determined by on-board computers linked to GPS satellites, experienced captains prefer to have a good old mechanical marine chronometer just in case.

Author of the article: Timur Baraev

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By accurately measuring time, a known fixed location such as Greenwich Mean Time (GMT) and the time at your current location. When first developed in the 18th century, it was a major technical achievement, since accurate knowledge of time during a long sea voyage is necessary for navigation without electronic or communication means. The first true chronometer was the life work of one man, John Harrison, spanning 31 years of persistent experimentation and testing, which revolutionized maritime (and later aerial) navigation and enabled the Age of Discovery and colonialism to accelerate.

Term chronometer was coined from Greek words chronosomes(time value) and meter(counter value) in 1714 by Jeremy Tucker, an early competitor for the prize established by the Law of Longitude that same year. Recently it has become more widely used to describe a watch that has been tested and certified to meet certain standards of accuracy. Timepieces made in Switzerland may display the word "chronometer" only if certified.

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To determine a location on the Earth's surface, it is necessary and sufficient to know latitude, longitude and altitude. Altitude considerations can naturally be ignored for ships operating at sea level. Until the mid-1750s, accurate navigation at sea from sight of land was an unsolved problem due to difficulties in calculating longitude. Navigators can determine their latitude by measuring the angle of the sun at noon (that is, when it has reached its highest point in the sky, or climax) or, in the northern hemisphere, by measuring the angle of Polaris (North Star) from the horizon (usually at dusk) . In order to find their longitude, however, they need a time standard that will work on board the ship. Observations of regular celestial movements, such as Galileo's method based on observations of the natural satellites of Jupiter, are usually not possible at sea due to ship motion. The lunar distance method, originally proposed by Johannes Werner in 1514, was developed in parallel with the marine chronometer. The Dutch scientist Gemma, Frisius Renier was the first to propose the use of a chronometer to determine longitude in 1530.

The purpose of a chronometer is to accurately measure time at a known fixed place, such as Greenwich Mean Time (GMT). This is especially important for navigation. Knowing GMT at local noon allows the navigator to use the time difference between the ship's position and the Greenwich meridian to determine the ship's longitude. Because the Earth rotates at a constant frequency, the time difference between the chronometer and the ship's local time can be used to calculate the ship's longitude relative to the Greenwich meridian (defined as 0°) using spherical trigonometry. In modern practice, a navigational almanac and trigonometric lookup tables allow navigators to measure the Sun, Moon, visible planets, or any of 57 selected stars for navigation at any time that the horizon is visible.

Creating a chronometer that would work reliably at sea was difficult. Until the 20th century, the best timekeepers had pendulum clocks, but both rolling ships at sea and up to 0.2% changes in Earth's gravity made the simple gravitational basis of the pendulum useless in both theory and practice.

The first marine chronometers

The first published use of the term was in 1684 in Arcanum Navarchicum, the theoretical work of Keel professor Matthias Wasmuth. This was followed by further theoretical descriptions of the chronometer in works published by the English scientist William Dyrham in 1713. Dyrham's main work, physico-theology or demonstration of the beings and attributes of God from his creation works, and also suggested the use of vacuum sealing to ensure greater accuracy in the operation of watches. Attempts to build a working marine chronometer were begun by Jeremy Tucker in England in 1714, and Henry Sully in France two years later. Sully published his work in 1726 with Une Orloga inventée et executée nominal M. Sulli, but neither his nor Tucker's model was able to withstand the rolling seas and maintain accurate time in shipboard conditions.

In 1714, the British government offered a longitude prize for a method of determining longitude at sea, with awards ranging from £10,000 to £20,000 (£2,000,000 million in £4 in 2019 terms) depending on accuracy. John Harrison, a Yorkshire carpenter, introduced the design in 1730, and in 1735 completed a clock based on a pair of counter-oscillating suspended beams connected by springs, the movement not being influenced by gravity or the motion of the ship. His first two marine chronometers, H1 and H2 (completed in 1741), used this system, but he realized that they had a fundamental sensitivity to centrifugal force, which meant they could never be accurate enough at sea. The construction of his third machine, designated H3, in 1759 included new annular remains and the invention of bimetallic strip and cage roller bearings, inventions that are still widely used today. However, the H3's circular remains still proved too inaccurate, and he eventually abandoned the larger machines.

Harrison solved the accuracy problems with his much smaller, H4 chronometer design in 1761. The H4 looked the same as a large five-inch (12 cm) diameter pocket watch. In 1761 Harrison presented H4 at Longitude for a prize of £20,000. Its design uses a fast-beating balance wheel, controlled by a temperature-compensated coil spring. These features remained in use until stable electronic oscillators allowed highly accurate portable watches to be made at an affordable price. In 1767 the Council of Longitude published a description of his work in Timekeeper's Principles by Mr. Harrison .

Modern chronometer

The most complete international collection of marine chronometers, including Harrison's H1 H4, is located at the Royal Observatory Greenwich, London, UK.

Mechanical chronometers

The decisive problem was to find a resonator that remained unchanged due to the changing conditions imposed on the ship at sea. A balance beam, drawn by a spring, solves most problems associated with the movement of a vessel. Unfortunately, the elasticity of most balance spring materials varies with temperature. To compensate for the ever-changing spring force, most chronometer remnants use a bimetallic strip to move small weights towards and away from the center of oscillation, thus changing the period of the balance to match the changing spring force. The spring balance problem was solved by using a nickel-steel alloy called elinvar for its constant elasticity at normal temperatures. The inventor was Guillaume, who won the 1920 Nobel Prize in Physics in recognition of his metallurgical work.

The descent serves two purposes. Firstly, it allows the train to fractionally and record balance fluctuations in advance. At the same time, it provides a negligible amount of energy to counteract the tiny losses due to friction, thereby maintaining the momentum of the oscillating balance. The escapement is the part that ticks. Because the natural resonance of the oscillating balance serves as the heart of a chronometer, chronometer escapements are designed to interfere with the balance as little as possible. There are many constant force and individual trigger mechanism designs, but the most common are the spring detent and the twist detent. In both of these, a small detent locks the escape wheel and allows the balance to swing completely free of disturbance for a short time, except at the center of vibration, when it is least subject to external influences. At the center of the oscillation, the roller on the balance staff momentarily displaces the detent, allowing one tooth of the escape wheel to pass through. The running wheel tooth then transfers its energy to a second roller on the balance staff. Since the travel wheel only turns in one direction, the balance only receives momentum in one direction. On reverse swings, a passing spring at the tip of the detent allows the roller to be unlocked by the staff to move without moving the detent. The weakest link of any mechanical timekeeper is the escapement's lubrication. As the oil thickens through age or temperature or humidity dissipates through or evaporation, the speed will change, sometimes dramatically, as the movement of the balance is reduced due to increased friction in the escapement. The locking escapement has a strong advantage over other escapements as it does not require lubrication. The pulse from the travel wheel to the pulse roller is almost dead beat, that is, the slightly moving action needs lubrication. The chronometer escape wheel and springs are usually gold due to the reduced sliding friction in the metal over brass and steel.

Chronometers often incorporate other innovations to improve their efficiency and accuracy. Hard stones such as ruby ​​and sapphire are often used as bearing jewels to reduce friction and wear on the trunnions and escapement. Diamond is often used as a cap stone for the lower swing end to prevent wear from years of heavy swing residue on the small swing end. Until the end of mechanical chronometer production in the third quarter of the 20th century, manufacturers continued to experiment with things like ball bearings and chrome-plated hinges.

Marine chronometers always contain a power maintainer, which keeps the chronometer going during its wound, and a power reserve to indicate how long the chronometer will continue to operate without being wound. Marine chronometers are the most accurate portable mechanical watches ever made, gaining accuracy of about 0.1 seconds per day or less than one minute per year. It is accurate enough to locate a ship's locations within 1-2 miles (2-3 km) after a month's sea voyage.

Marine chronometer 32043 was manufactured at the Polet plant according to TU 25-07.1533-84.
The chronometer was developed by specialists from the 1st Moscow Watch Factory in 1947 and was intended to store exact time in hours, minutes and seconds on ships and vessels of all classes, types and purposes. In 1949, the industrial production of marine chronometers began, which continues to this day. The marine chronometer was exported to Bulgaria, Vietnam, Germany, Poland, Romania, Finland, Czechoslovakia, Yugoslavia, Japan, Italy, America and other countries.
The marine chronometer case is suspended by a gimbal inside a wooden case, which is placed in an outer case equipped with soft inner lining and a strap for carrying the chronometer.
The outer and inner case of the chronometer is made of mahogany.
In the center of the dial, divided into 12 o'clock, there are hour and minute hands, moving along a common dial. Below is the second hand, which moves around the seconds dial in jumps every 0.5 seconds. At the top of the chronometer dial there is a winding dial, divided by lines into seven parts of 8 hours each. The digitization of intervals is given from 0 to 56 hours, i.e. The maximum winding time is 56 hours of chronometer operation.
A hand moves across the winding dial, indicating the number of hours that have passed since the chronometer was wound.
The chronometer should be wound at the same time every day (for example, at 8 a.m.) so that the same part of the spring acts during each day, which ensures a constant daily rate. Usually the chronometer is wound so that it can run for two days, i.e. After winding, the winding needle should point to the 8 o'clock position.
Before winding, subject to regular winding at the same time, the hand of the winding dial should point to the division with the number 32 o'clock.
The chronometer is a unique hand-assembled mechanism with a chronometer escapement on ruby ​​stones and a balance support made of natural diamond. The chronometer is installed in a case and box made of hardwood with a glossy varnish coating in the color of mahogany, or, upon additional order, from mahogany. An analogue of the 6MX marine chronometer is produced by only one company - the Swiss company Zenit. The marine chronometer is on display at the Swiss Clock Museum in Chaux-de-Fonds.
A marine chronometer is mandatory equipment in the ship's registry of the world famous insurance company Lloyd's.
Technical data:
Average deviation of the daily cycle +-0.35 s
Travel recovery +-2.00 s
Maximum variation of the diurnal cycle +-2.30 s
Temperature coefficient +- 0.10 s/deg
Secondary compensation error +-1.20s
Average daily cycle of any period +- 3.50 s
Estimated number 30
Overall dimensions of the box - 250x250x250 mm
Weight no more than 2.2 kg.
Information about the content of precious materials:
Gold 1.1784 g
Silver 0.8563 g
Alloy Zl SRM 333-333 0.0180 g
Diamond 0.07...0.1 carats
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