Terms and definitions, dictionary
Geographical (real, "solar", sidereal) time- determined by geographic location any particular point on the surface of the earth. On the time map () - its values, relative to the original Greenwich prime meridian, are shown in numbers along the upper and lower edges of the map ("plus" means - to the east, "minus" - to the 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 earlier than real time in the morning). 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 shifting of the clock forward one hour, which was carried out annually on the last Sunday of March, in order to get an extra hour during daylight hours, to save electricity (for lighting, etc.). The return to winter time was carried out in the last. Sunday October. These transitions affected the biorhythms of the human body, his well-being, and it took a week of adaptation to get used to. Manipulation of the hands of the clock is a common cause of lateness of workers and employees to work.
Primary (zero) meridian– The Greenwich meridian with geographic longitude equal to 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 Mean Time"- on the meridian Greenwich. It is determined by astronomical observations of the daily movement of stars. It is unstable (within a second per year) and depends on the constant change in the speed of the Earth's rotation, the movement of the geographic poles on its surface and the nutation of the planet's axis of rotation. Greenwich (astronomical) time is close in value to UTC (atomic time), and for the time being will be used as its synonym. Also called "Zulu Time"
In Russian-speaking meteorology, GMT is denoted as GMT (Greenwich Mean / or Geographic / Time)
GMT= UTC (accurate to 1 second)
Timezone(Standard time zone) - difference from UTC/GMT World Time (example: UTC/GMT+4 - the 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 12-hour format (abbreviated version - "A")
RM- designation of the time after noon in 12-hour format
UTC(Universal Time - Universal time) - the average solar time on the meridian Greenwich, is determined from astronomical observations of the daily motions of stars. Its refined values are UT0, UT1, UT2
UT0- time on the instantaneous Greenwich meridian, determined by the instantaneous position of the Earth's poles
UT1– time on 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. It does not include amendments. It is ahead of the UTC time by 15 seconds.
UTC(from English Universal Time Coordinated) - Coordinated Universal Time for the coordinated distribution of standard frequencies and accurate time signals via radio, television and the Internet - World, "World Time". Its synonym is "Universal Time Zone"
time scale UTC introduced since 1964 to harmonize UT1 (astronomical measurements) and TAI (atomic clocks).
Unlike GMT, UTC is set using atomic clocks.
The speed of rotation of the earth is slowing down, and therefore, in the UTC scale, regularly, after a year or two or three, on June 30 or December 31, clarifying amendments are introduced (leap seconds - leap "Second of coordination"), 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 ratio of time after December 31, 2016:
UTC (universal) is behind TAI (atomic) by 37 s.
T glonass = Tutc + 3 hours
Time Signals(for clock synchronization) are transmitted over radio channels, television, the Internet - in the UTC system. More precisely, you can put, for example, on the signal of the Mayak radio, but only on the long-wave or medium-wave range (on the "earth-surface wave"). On the VHF / FM radio band, the signal may be delayed up to several seconds from the true one.
In watches with automatic synchronization (eng. Radio controlled), time correction occurs from base stations, on ultra-long waves. This system has been developed in Europe.
Numbers of exact local time services (local time) in Russian cities
100 - Moscow, Voronezh, Cheboksary, Chelyabinsk
060 - Bryansk, Kaliningrad, Krasnodar, Murmansk, St. Petersburg, Samara
At mobile operators there is no such 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 translated in winter or summer, therefore, for those places where there is a translation for summer time, bias changes relative to UTC (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 English language(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 (GMT) - the time of the meridian passing through the old Greenwich Observatory near London. It is used as a designation of time on weather charts. Synonyms for GMT are GMT and UTC.
"Time and calendar" - M .: Nauka. 1989
Www.ru.wikipedia.org/wiki/Timezones
Https://time.yandex.ru - Calculator for calculating the time difference between cities.
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 counting according to Greenwich Mean Time?
Greenwich is known as 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 long been associated with the British Navy.For all time zones there is a so-called reference point - this is the place where the Greenwich Observatory used to be. This observatory became a starting point not by chance. The observatory was formed in the seventeenth century; calculations were carried out there, which were of great importance for navigators. The calculations concerned, including 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 dependent states. By the end of the nineteenth century, this system was adopted throughout the world. In 1884, at a special conference, it was decided to determine the "reference meridian". Depending on the distance from this meridian, the time in other regions was determined. Time zones were designated, starting from the zone in which Great Britain is located. Thus, universal time was synchronized.
The world time reference system 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 in the seventeenth century by Charles II, there is a museum of navigational and astronomical devices. The observatory itself was withdrawn from this building back in 1990 due to light blockage. Now it is located nearby in Greenwich Park.
It is known that Moscow time is four hours longer than Greenwich Mean Time. One of the ways to find out the exact Moscow time is to use the Internet, call, find out by radio or via satellite. All regions of Russia are guided by Moscow time, and the countdown goes the same way from Moscow time. Due to the stretch, the country is located in nine time zones.
Who came up with the exact time?
A lot of mechanisms have been invented by man to measure time. In ancient times, people measured time in sunrises and sunsets, paid attention to the increase or decrease in the shadow of objects throughout the day. Thanks to this, people could roughly navigate in time. The role of a huge clock was performed by the stars. It was noticed that in different periods At night, different stars are visible in the sky.The ancient Egyptians, as a result of observing the stars, divided the night into twelve intervals. At the same time, they focused on the moments of the appearance of each of the twelve stars. It can be concluded 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. Water and fire were also used to measure time.
The first hourglass appeared two thousand years ago. But the first mechanical clock was invented more than one thousand four hundred years ago. A coil with a chain was attached to the mechanism of this watch, at the end of which there was a weight. Thanks to the load, the coil rotated, while the chain unwound. With the help of a regulator and a series of gears, an arrow moved along 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 - 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 lie in how accurate the measurements are for each particular watch. 
Every second must be the same time. This is influenced by the oscillatory rhythm created by the pendulum, the vibration of quartz, the 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. Clocks can deviate by one second in one hundred and thirty-eight million years. Watches "from cesium" were jointly created by scientists from Japan and America in one of the European laboratories.
In February 2010, American scientists created an atomic clock that surpassed those made from cesium. It took several years of development, resulting in an aluminum-based watch that could be a second behind in three billion seven hundred million years. The name of this novelty is Quantum Logic Clock.
This clock is able to divide time into much smaller intervals, which in the future can be used to test various constants and laws of physics.
The exact time is measured in hours. These mechanisms are not always simple. Blancpain 1735 watches cost 800 thousand dollars .. You can read a detailed article on this topic.
Subscribe to our channel in Yandex.Zen
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 the material, we tried to collect all the necessary information about time zones and world time settings for all types of dials [from digital to arrow]. If you like to travel and want to always be aware of the time at the 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 function. In other words, it is a display of the current time in major cities and specific areas around the world. World time is closely related to time zones, the appearance 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 a non-uniform 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 winter or summer, so for places where there is a change to summer time, the offset relative to UTC changes.
The timeline is divided into 31 time zones located around 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-to-digital, but the principle of working with world time is different. Let's start with digital models, using the [module 3410] series as an example.
- Enter the world time mode by pressing the D button. The WT indicator will appear on the screen and the current set world time city code and name will flash after a second.
- Use buttons A and C to select the desired area code.
Set standard/daylight saving 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 that, you can release the button. This will turn on [or off] daylight saving time for the selected area code.
- If you change this setting for the city code of your current location while in World Time Mode, the setting for Timekeeping Mode will also change.
- Daylight saving time setting is performed only for the selected area code, for other area codes, the setting is not changed.
For example g-shock [module 5502], we will analyze the world time setting 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 applied along the entire length of the bezel. Thus, the problem of indicating cities is solved.
- For each of the area codes, you can roughly see the 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 button B is pressed, the mode hand will move to the daylight saving time setting.
AT (AUTO) - switching to daylight saving time and back is performed automatically.
STD - The clock always shows standard time.
DST - The clock always shows daylight saving time.
- To change the summer time setting, hold down button B for 1 second. Each time you do this, the daylight saving time setting changes to the next 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 the current and world time, press and hold the B button.
You can select UTC [Coordinated Universal Time] as the city 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.
