In our life, counting and measuring time is of great importance. To measure it, watches were invented: mechanical, solar, sand, wrist, pocket. I wonder how the most accurate time is measured?

Why is the exact time counted according to Greenwich?

Greenwich is called the "sea gate" of London. Initially it was a suburb, but now it is an administrative district located in the southeast of the capital. Greenwich is located on the right bank of the Thames and has been associated with the British Navy for a long time.

For all time zones there is a so-called reference point - this is the place where the Greenwich Observatory used to be. It was not by chance that this observatory became the starting point. The observatory was founded in the seventeenth century; calculations of great importance for seafarers were carried out there. The calculations also concerned the exact time.

Due to the fact that Great Britain became the most powerful empire, the calculation of time, carried out at the Greenwich Observatory, was also extended to the dependent states. By the end of the nineteenth century, this system was widely accepted throughout the world. In 1884, at a special conference, it was decided to determine the “meridian of reference”. Depending on the distance from this meridian, time was determined in other regions. Time zones were designated, starting from the zone in which Great Britain is located. Thus, universal time was synchronized.

The time system in the world in the seventies was replaced by another, more accurate one, which differs from the time of the Greenwich meridian. Despite this, the well-known abbreviation GMT continues to be used, which looks like a tribute to tradition.

In the building of the old observatory, which was founded by Charles II in the seventeenth century, there is a museum of navigational and astronomical devices. The observatory itself was removed from this building back in 1990 due to light pollution. It is now located nearby in Greenwich Park.

It is known that Moscow time is four hours longer than Greenwich time. One way to find out the exact Moscow time is to use the Internet, call by phone, find out on the radio or via satellite. All regions of Russia are guided by Moscow time, and the countdown also starts from Moscow time. Due to its sprawl, the country is located in nine time zones.

Who came up with the exact time?

Man has invented many mechanisms to measure time. In ancient times, people measured time at sunrises and sunsets, and paid attention to the increase or decrease in the shadows of objects throughout the day. Thanks to this, people could approximately navigate in time. The role of a huge clock was played by the stars. It has been observed that different stars are visible in the sky at different times of the night.

The ancient Egyptians, as a result of observing the stars, divided the night into twelve intervals. At the same time, they were guided by the moments of appearance of each of the twelve stars. We can conclude that the division of the day into twenty-four hours originated precisely from the division of the night by the Egyptians into twelve time intervals.

Shadow or sundials were also created by the Egyptians. It was a simple board with marks, which became the first prototype of a device for measuring time. To measure time they also used water and fire.

The first hourglass appeared two thousand years ago. But the first mechanical watches were invented more than one thousand four hundred years ago. Attached to the mechanism of this watch was a reel with a chain, at the end of which there was a weight. Thanks to the load, the coil rotated, and the chain unwinded. Using a regulator and a series of gears, the arrow moved across the dial.

For centuries, the smallest division of time was the hour. In 1860, one of the London watchmakers managed to make a watch that showed not only minutes and hours, but also seconds.

The most accurate time in the world

Whatever the clock is - old, new, small or large, expensive or cheap, wrist, pocket or wall, they are in any case designed to measure time. The difference between them can only be how accurate the measurements are for each specific watch.

Each second should last the same amount of time. This is influenced by the oscillatory rhythm created by the pendulum, vibration of quartz, spring, etc. For several years, cesium clocks containing “atomic time” were considered the most accurate clocks. It was the most accurate long-term timekeeper in the world. A clock can be off by one second in one hundred and thirty-eight million years. The “cesium” watch was jointly created by Japanese and American scientists in one of the European laboratories.

In February 2010, American scientists created an atomic clock that surpassed those made from cesium. Development took several years, resulting in an aluminum-based watch that can move one second in three billion seven hundred million years. The name of this new product is Quantum Logic Clock.

These clocks are capable of dividing time into much smaller intervals, which in the future can be used to test different constants and laws of physics.

Exact time is measured by a clock. These mechanisms are not always simple. The Blancpain 1735 watch costs 800 thousand dollars. You can read a detailed article on this topic.
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And time zones. The function is available in most models of this manufacturer and is used to view the current time in major cities around the world. In this material, we tried to collect all the necessary information about time zones and world time settings for all types of dials [from digital to dial]. If you love to travel and want to always be aware of the time at your point of arrival, study the article and perhaps you will learn something new and useful for yourself.

Most Casio watches have a world time display feature. In other words, it displays the current time in major cities and specific areas around the world. World time is closely related to time zones, the emergence of which was due to travel. For example, you often go on business trips, and there is no particular desire to manually change the time every time you arrive at your destination, which is located on the other side of the world. Or, for example, you plan to call a friend in Australia at lunchtime, but you don’t want to wake him up in the middle of the night.

Today, world time is governed by the UTC standard. Differs from atomic time by an integer number of seconds. UTC was introduced as a replacement for GMT [Greenwich Mean Time] because the latter was an uneven scale and was related to the daily rotation of the Earth. The UTC scale is more accurate and uniform, and therefore more convenient to use. It is worth noting that UTC time is not converted in either winter or summer, so for places where there is a conversion to daylight saving time, the offset relative to UTC changes.

The timeline is divided into 31 time zones, located throughout the world. For clarity, we will show city ​​code table with a time offset relative to UTC.

Because Casio watches are digital, analog and analog-digital, but the principle of working with world time is different. Let's start with digital models, using the [3410 module] series as an example.

• Enter World Time mode by pressing the D button. The WT indicator will appear on the screen and after a second the currently set World Time city code and its name will begin to flash.
• Use buttons A and C to select the desired area code.

Set standard/summer time for the selected area code.

• In world time mode, select the desired area code.
• Press and hold the E button for 2 seconds until the DST HOLD indicator is displayed, then HOLD disappears. After this you can release the button. This will enable [or disable] daylight saving time for the selected area code.
• In world time mode, if you change this setting for the current location's city code, the current time mode setting will also change.
• The summer time setting is performed only for the selected city code; for other city codes, the setting is not changed.

For example G-Shock [module 5502], let's look at setting the world time in a watch with an analog dial.

• Pull the crown out to the first click. The second hand will indicate the currently selected world time city code. In analog watches, city codes are printed along the entire length of the bezel. In this way, the problem of indicating cities is solved.
• For each city code, you can see the approximate latitude and longitude values.

• To change the world time city code, turn the crown. In this case, the hour and minute hands will show the current time for the selected city.

• If you press the B button, the mode hand will move to the summer time setting.

AT (AUTO) – switches to and from daylight saving time automatically.
STD – The clock always shows standard time.
DST - The clock always shows daylight saving time.

• To change the daylight saving time setting, hold down button B for 1 second. Each time you do this, the daylight saving time setting changes to the following setting.
• Return the crown to its original position.

Cautions

• If UTC is selected as the city time, switching between STD and DST modes will not be possible.

To switch between current and world time, press and hold the B button.

You can select UTC [Coordinated Universal Time] as the area code for world time. To do this, press and hold button A for about a second. The hour and minute hands will show the current UTC time.

Terms and definitions, dictionary

Geographical (real, solar, sidereal) time– determined by the geographic location of each specific point on the Earth’s surface. On the map of time () - its values, relative to the original Greenwich prime meridian, are shown in numbers along the upper and lower edges of the map ("plus" means east, "minus" means west of Greenwich). For example, now, in the city of Moscow, the calculated difference with real time is approximately half an hour (this is exactly how much you have to get up in the morning before real time). Until October 26, 2014, when the country lived according to fixed summer time, the time shift forward from real time was even greater - plus 1.5 hours.

Go to Daylight Saving (Summer) Time (DST)- seasonal movement of the clock hand one hour forward, which was carried out annually on the last Sunday of March in order to gain an additional hour during daylight hours, to save electricity (for lighting, etc.). The return to winter time was carried out recently. Sunday in October. These transitions affected the biorhythms of the human body, his well-being, and it took a week of adaptation to get used to it. Manipulation of clock hands is a common reason why workers and employees are late for work.

Primary (zero) meridian– The Greenwich meridian, with a geographic longitude of 0°00"00", divides the globe into the western and eastern hemispheres. Passes through the former Greenwich Observatory (in the suburbs of London)

GMT (Greenwich Mean Time) - "Greenwich Time"- on the meridian Greenwich. Determined from astronomical observations of the daily motion of stars. It is unstable (within a second per year) and depends on the constant change in the speed of rotation of the Earth, the movement of geographic poles along its surface and the nutation of the planet’s rotation axis. Greenwich (astronomical) time is close in meaning to UTC (atomic time), and will still be used as its synonym. Another name is “Zulu Time”

In Russian-language meteorology, GMT is designated as SGV (Greenwich Mean / or Geographical / Time)

GMT= UTC (accurate to 1 second)

Timezone(Standard time zone) – difference from World Time UTC/GMT (example: UTC/GMT+4 - fourth time zone, east of Greenwich)

H:mm:ss – 24 hour format(example: 14:25:17). Minutes and seconds – with leading zeros

h:mm:ss – 12 hour format(example: 02:25:17 PM – “two and a half hours in the afternoon” – 14:25:05). Minutes and seconds – with leading zeros

AM– designation of time before noon in a 12-hour format (short version – “A”)
RM– designation of time after noon in a 12-hour format

UTC(Universal Time) - average solar time on the meridian Greenwich, is determined from astronomical observations of the daily movements of stars. Its specified values ​​are UT0, UT1, UT2

UT0– time at the instantaneous Greenwich meridian, determined from the instantaneous position of the Earth’s poles

UT1– time at the Greenwich mean meridian, corrected for the movement of the earth's poles

UT2- time, taking into account changes in the speed of rotation of the Earth

TAI– time according to atomic clocks (International Atomic Time, since 1972). Stable, reference (most accurate), never translated. Time and frequency standard.

Time in GPS navigation system has been operating since January 1980. No amendments are introduced to it. It is ahead of UTC time by one and a half dozen seconds.

UTC(from English Universal Time Coordinated) - Universal coordinated time for the coordinated distribution of standard frequencies and time signals via radio, television and the Internet - Universal, "World Time". Its synonym: "Universal time zone"

time scale UTC introduced since 1964 to harmonize UT1 (astronomical measurements) and TAI (atomic clocks).

Unlike Greenwich Mean Time, UTC is set using atomic clocks.

The speed of rotation of the earth is slowing down, and therefore, in a year or two or three, on June 30 or December 31, clarifying amendments are introduced into the UTC scale (leap seconds) so that U T C is no more than second (more precisely, 0.9 s) differed from astronomical time (determined by the movement of the Sun), as UT1 lagged behind by a second. This international rule was adopted in 1972.

For example, the time ratio after December 31, 2016:
UTC (universal) lags behind TAI (atomic) - by 37 s.
T glonass = Tutc + 3 hours (adjustable so the difference between them does not exceed 1 ms.)

Time Signals(for clock synchronization) are transmitted over radio channels, television, the Internet - in the UTC system. More precisely, you can place it, for example, on the Mayak radio signal, but only on the long-wave or medium-wave range (on the “ground-surface wave”). On VHF/FM radio, the signal may be delayed up to several seconds from the true one.

In watches with automatic synchronization (English Radio controlled), time correction occurs from base stations, on ultra-long waves. This system was developed in Europe.

Numbers of exact local time services in Russian cities
100 – Moscow, Voronezh, Cheboksary, Chelyabinsk
060 – Bryansk, Kaliningrad, Krasnodar, Murmansk, St. Petersburg, Samara

Mobile operators do not have such a service, since the mobile phone is not limited geographically
and can work not only in a certain city, but also in roaming.

UTC time is not converted neither in winter nor in summer, therefore, for those places where there is a change to daylight saving time, bias relative to UTC changes (in Moscow, before the abolition of winter time in 2011, the difference was: in winter – UTC+3, and in summer – UTC+4).

Standard abbreviations names of calendar months and days of the week in English (used in RSS and others):

January February March April May June
Jan Feb Mar Apr May Jun

July August September October November December
Jul Aug Sep Oct Nov Dec

Monday Tuesday Wednesday Thursday Friday Saturday Sunday
Mon Tue Wed Thu Fri Sat Sun

SGV– Greenwich Mean Time (or Geographical) Time (Greenwich Mean Time, GMT) is the time of the meridian passing through the old Greenwich Observatory, near London. Used to indicate time on weather maps. Synonyms for GW are GMT and UTC.

“Time and calendar” - M.: Nauka. 1989

Www.ru.wikipedia.org/wiki/Time_zones

Https://time.yandex.ru – Calculator for calculating time differences between cities.

Time in the era of information technology has become of particular importance for modern man. Each of us at least several times a day glances at the clock. Many people regularly synchronize their time reporting devices through various sources, including the Internet. Accurate time sometimes plays a decisive role in matters where not even minutes, but seconds are important. For example, trading on the stock exchanges can turn into a crash for a player whose clock showed the wrong time. Let's try to set up our electronic clock on a computer and synchronize the exact time via the Internet.

Time synchronization technology

First, I’ll tell you a little about the technology used to obtain accurate time from Internet sources. The entire time synchronization process is carried out through a special network protocol called NTP (Network Time Protocol). This protocol is a set of various rules and mathematical algorithms, thanks to which the time on your computer is precisely adjusted with a difference of a few hundredths of one second. There is also a protocol for systems that do not require such precise synchronization, called SNTP. The difference between the source and the receiving device can be up to 1 second.

The technology for transmitting precise time parameters is a multilayer structure, where each underlying layer of electronic devices is synchronized with the underlying one. The lower the technological layer, the less accurate the time obtained from it will be. But this is in theory, in practice everything depends on many parameters involved in the synchronization system and more accurate time can be obtained, for example, from the fourth layer of devices than from the third.

At the zero level of this transmission chain there are always time reporting devices, roughly speaking, clocks. These clocks are molecular, atomic or quantum time-keeping devices and are called reference clocks. Such devices do not transmit time parameters directly to the Internet; they are usually connected to the primary computer via a high-speed interface with minimal delays. It is these computers that make up the first layer in the technological chain. On the second layer there will be machines that receive time from the first layer of devices via a network connection, most often via the Internet. All subsequent layers will receive information about the exact time using the same network protocols from the overlying layers.

Time synchronization in Windows

Let's try to synchronize time using systems Windows XP, Windows 2003 . To do this, click on the clock that is located in your tray (usually in the lower right corner of the screen) to bring up the date and time settings. In this case, be sure to check the settings “ time zone”, which are located there and adjust them if necessary.

For Windows Vista, Windows 7 You can also just click on the clock at the bottom of the screen and go to the settings through the special link “Changing date and time settings”

Then go to the “Internet Time” tab and click the “Change Settings” button.

An Internet time settings window will appear, similar to the same window from Windows XP, 2003.

In this window there is an option to automatically reconcile hours via the Internet, which is available opposite the inscription “ Synchronize with an Internet time server" If you enable it by checking the box, then periodically the time of your computer will be updated via the Internet server by the operating system itself.

Next, opposite the option “ Server:“The user can choose from a list of addresses from which synchronization will be carried out. Try selecting one of them and clicking the “ Update now" If after a certain time an inscription about a synchronization error appears under the list, manually enter one of the server addresses below and check the connection with it.

ntp.mobatime.ru nist1-ny.ustiming.org ntp.chg.ru

Below is a video that will show the process of setting up the system clock in Windows 7 and synchronizing it.

Changing the automatic time synchronization period in Windows

By default, the Windows operating system accesses synchronization servers only once a week. Provided that the user has set automatic time checking, of course. For some, this period may seem quite long or may be quite frequent than would be desirable. Fortunately, the system allows you to change this parameter through the registry settings.

Open the window " Run” through the menu “ Start" At the command line, type regedit and start with the “ OK" You need to get to the next section one by one

HKEY_LOCAL_MACHINE - SYSTEM - CurrentControlSet - Services - W32Time - TimeProviders - NtpClient

and select the option in the window on the left SpecialPollInterval. The value is given here 604800 , if you convert it to the decimal system. This number of seconds is equal to one week. Here you can enter another value that you need, converting it into seconds.

In addition to the clock running on your computer, there are probably other sources of time that you have to periodically check so as not to get out of the general work schedule or schedule. Clocks can be wall, table, or wrist, and the accuracy of the time shown by them does not always correspond to reality. Meanwhile, trying to synchronize the time of these devices manually, many turn to television sources. However, such means can transmit signals with significant delays, so it is impossible to guarantee accurate time to at least a minute from these sources.

Fortunately, there are many timekeeping services available on the global web that will help you set your watch to the correct time, down to one second. Of course, the Internet is not blameless in terms of time delays in the transmission of information, but such delays with good communication usually do not amount to more than one second.

Multifunctional service for displaying exact time. In addition to its main purpose, it allows you to check the clocks of various time zones, find out the calendar information of the current day, fine-tune the format for displaying time on the screen through the site and the display style, display the calendar of the current year, find out the time in any of the cities of the world and much more. Perhaps one of the most useful and versatile time services I have ever worked with.

A beautiful image of a dial with moving hands will delight fans of stylish virtual design. In addition to information about the exact time, here you can find data on the time of sunrise and sunset in your region, as well as a link to the weather forecast for the specified city.

There is practically nothing superfluous on the screen, only basic information about the exact time, plus the ability to compare it with the clock of your system. However, there is a small menu with additional functions, such as the remaining time until the end of the world according to the Mayan calendar, a stopwatch, a date converter and a time zone map.

You also have access to other web resources that may help you resolve your issues.