Time and calendar. Exact time and determination of geographic longitude

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Text content of presentation slides: Measuring time. Determination of geographic longitude. Prepared by Trofimova E.V. Geography and astronomy teacher State Educational Institution "Secondary School No. 4 of Orsha" Purpose of the lesson Formation of a system of concepts about instruments for measuring, counting and storing time. Objectives: Define time. What determines the length of the day and year? How is Universal Time determined? What is the reason for the introduction of standard time ?Learn to determine geographic longitude Lesson plan1. Time measurementa) true solar time; b) mean solar time2. Determination of geographic longitudea) local time; b) universal time; c) zone system; d) summer time3. Calendar) lunar calendar. b) lunisolar calendar c) Julian calendar d) Gregorian calendar Ancient Greek god of time Kronos The main property of time is that it lasts, flows non-stop. Time is irreversible - traveling to the past with a time machine is impossible. “You cannot enter the same river twice,” said Heraclitus. Ancient myths reflected the important meaning of time. The basic unit of time is the day, month, year. The main unit of time measurement is associated with the period of rotation of the globe around its axis of rotation. Time is a continuous series of successive phenomena. Sundials are very diverse in shape. For a long time, time was measured in days according to the time the Earth rotates around its axis. Thousands of years ago, people noticed that many things in nature repeat themselves: the Sun rises in the east and sets in the west, summer gives way to winter and vice versa. It was then that the first units of time arose - day, month and year. Using simple astronomical instruments, it was established that there are about 360 days in a year, and in approximately 30 days the silhouette of the Moon goes through a cycle from one full moon to the next. Therefore, the Chaldean sages adopted the sexagesimal number system as a basis: the day was divided into 12 night and 12 day hours, the circle - into 360 degrees. Every hour and every degree was divided into 60 minutes, and every minute into 60 seconds. The day is divided into 24 hours, each hour is divided into 60 minutes. In ancient times, people determined time by the Sun. The ancient Indian observatory in Delhi, which also served as a sundial. The majestic Stonehenge is one of the oldest astronomical observatories, built five thousand years ago in Southern England. Already in those days they were able to determine time by the moment of sunrise. Solar calendar of the ancient Aztecs Subsequent more accurate measurements showed that the Earth makes a complete revolution around the Sun in 365 days 5 hours 48 minutes and 46 seconds, i.e. for 365.25636 days. The Moon takes from 29.25 to 29.85 days to go around the Earth. The period of time between two culminations of the Sun is called a solar day. They begin at the moment of the lower culmination of the Sun on a given meridian (i.e. at midnight). Solar days are not the same - due to the eccentricity of the earth's orbit, in the winter in the northern hemisphere the day lasts a little longer than in the summer, and in the southern hemisphere it is the other way around. In addition, the plane of the ecliptic is inclined to the plane of the earth's equator. Therefore, an average solar day of 24 hours was introduced. Big Ben Clock in London The time elapsed from the moment of the lower culmination of the center of the solar disk to any other position on the same geographical meridian is called true solar time (TΘ). The difference between mean solar time and true solar time at the same time the same moment is called the equation of time η. (η= ТΘ - Тср)Greenwich. London Mean solar time, counted from midnight, is not called universal time on the Greenwich meridian. Denoted by UT (Universal Time). Local time is convenient for everyday life - it is associated with the alternation of day and night in a given area. In an area with geographic longitude λ, local time (Tλ) will differ from universal time (To) by the number of hours, minutes and seconds equal to λ: Tλ = To + λ To eliminate discrepancies in time counting in different localities, it is customary to divide the earth's surface into time zones. 24 earth meridians were selected (every 15 degrees). From each of these 24 meridians we measured 7.5° in both directions and drew the boundaries of time zones. Within time zones, time is the same everywhere. Zero zone – Greenwich. The Prime Meridian passes through the Greenwich Observatory, located near London. At each of these meridians, standard time differs from universal time by an integer number of hours equal to the zone number, and the minutes and seconds coincide with Greenwich Mean Time. In our country, standard time was introduced on July 1, 1919. There are 11 time zones across Russia (from II to XII inclusive). Knowing the universal time (To) and the zone number of a given place (n), you can easily find the standard time (Tp): Tp = To + nZero meridian. Greenwich. LondonIn 1930, all clocks in the former Soviet Union were set forward an hour. And in March, Russians move their clocks forward another hour (i.e. already 2 hours compared to standard time) and until the end of October they live according to summer time: Tl = Tp +2h Moscow time is the local time in the capital of Russia, located in II time zone. According to Moscow winter time, true noon in Moscow occurs at 12 hours 30 minutes, according to summer time - at 13 hours 30 minutes. Problem On May 25 in Moscow (n1 = 2), the clock shows 10:45. What is the average, standard and summer time at this moment in Novosibirsk (n2 = 6, 2 = 5h31m)? Given: Tl1 = 10h 45m; n1 = 2; n2 = 6; 2 = 5h 3mFind: T2 - ? (average time - local time in Novosibirsk) Тп2 - ? Tl2 - ? Solution: Find the universal time T0: Tn1 = T0 + n1; Tl1 = Tn1+ 2h; Т0 = Тl1– n1 – 2h; T0 = ​​10h 45m – 2h – 2h = 6h 45m; We find average, standard and summer time in Novosibirsk: T2 = T0 + 2; T2 = 6h 45m + 5h 31m = 12h 16m; Tn2 = T0 + n2; Тп2 = 6h 45m + 6h = 12h 45m; Tl2 = Tn2+ 2h; T2 = 12h 45m + 2h = 14h 45m. Answer: T2 = 12h 16m; Тп2 = 12h 45m; Tl2 = 14h 45m; What can you say about the presented drawings? What instruments for measuring time do you know? Types of watches The simplest chronometric instruments: sand solar floral water fire Mechanical watches: mechanical quartz electronic GOU Secondary School No. 4 Instruments for measuring and storing time The history of the development of watches - means for measuring time - is one of the most interesting pages in the struggle of human genius for understanding and mastering the forces of nature. The first clock was the Sun. The first instruments for measuring time were sundials, then equatorial sundials. GOU Secondary School No. 4 Sundial The appearance of this clock is associated with the moment when a person realized the relationship between the length and position of the sun's shadow from certain objects and the position of the Sun in the sky. The gnomon, an upright obelisk with a scale marked on the ground, was the first sundial to measure time by the length of its shadow. Hourglasses Later, hourglasses were invented - funnel-shaped glass vessels, placed one on top of the other and the top one filled with sand. They could be used at any time of the day and regardless of the weather. They were widely used on ships. Fire clocks Fire clocks, which were widely used, were more convenient and did not require constant supervision. One of the fire clocks used by the miners of the ancient world was a clay vessel with enough oil to burn the lamp for 10 hours. As the oil burned out in the vessel, the miner finished his work in the mine. In China, for fire watches, dough was prepared from special types of wood, ground into powder, along with incense, from which sticks of various shapes were made, or more often long, several meters long in a spiral. Such sticks (spirals) could burn for months without requiring maintenance personnel. There are known fire clocks that are also an alarm clock. In these clocks, metal balls were suspended from a spiral or stick in certain places, which, when the spiral (stick) burned, fell into a porcelain vase, producing a loud ringing. Fire clocks in the form of a candle with marks were widely used. The combustion of the candle segment between the marks corresponded to a certain period of time. Water clockThe first water clock was a vessel with a hole from which water flowed out over a certain period of time. Mechanical watchesAs the productive forces developed and cities grew, the requirements for instruments for measuring time increased. At the end of the 11th - beginning of the 12th centuries. Mechanical watches were invented, marking an entire era. A significant step in the creation of mechanical watches was made by Galileo Galilei, who discovered the phenomenon of isochronism of a pendulum with small oscillations, i.e. independence of the oscillation period from the amplitude. Electronic clock Electronic clock, a clock in which periodic oscillations of an electronic generator are used to keep time, converted into discrete signals, repeating after 1 s, 1 min, 1 h, etc.; signals are displayed on a digital display showing the current time, and in some models also the day, month, day of the week. The basis of an electronic watch is a microcircuit. Even more accurate watches that replaced mechanical ones were quartz watches. Calendar The centuries-old history of mankind is also inextricably linked with the calendar, the need for which arose in ancient times. The calendar allows you to regulate and plan life and economic activities, which is especially necessary for people involved in agriculture. As a result of attempts to coordinate the day, month and year, three calendar systems arose: lunar, in which they wanted to coordinate the calendar month with the phases of the Moon; solar, in which they sought to reconcile the length of the year with the periodicity of processes occurring in nature: lunisolar, in which they wanted to reconcile both. The whole variety of permanent calendars can be divided into analytical calendars - formulas of varying complexity, allowing for a given date to calculate the day of the week of any past and future calendar date, and tabular - tables of various designs with both fixed and moving parts. CalendarA calendar with leap years is called Julian. It was developed on behalf of Julius Caesar in 45 BC. The Julian calendar gives an error of one day every 128 years. The Gregorian calendar (the so-called new style) was introduced by Pope Gregory XIII. In accordance with a special bull, the count of days was moved forward 10 days. The next day after October 4, 1582 began to be considered October 15. The Gregorian calendar also has leap years, but it does not consider leap years for centuries in which the number of hundreds is not divisible by 4 without a remainder (1700, 1800, 1900, 2100, etc.). Such a system will give an error of one day in 3300 years. On the territory of our country, the Gregorian calendar was introduced in 1918. In accordance with the decree, the count of days was moved forward 13 days. The next day after January 31 began to be considered February 14. Currently, the Christian era is used in most countries of the world. The counting of years begins from the Nativity of Christ. This date was introduced by the monk Dionysius in 525. All years before this date became known as “BC,” and all subsequent dates became “AD.” Number of days in the months of the Julian calendar months months name number of days name number of days January 31 Quintilis 31 February 29 and 30 Sextilis 30 March 31 September 31 April 30 October 30 May 31 November 31 June 30 December 30 Number of days in months in the original Roman calendar months months name number of daysnamenumber of daysMarch31 September 29 April 29 October 31 May 31 November 29 June 29 December 29 Quintilis 31 January 29 Sextilis 29 February 28 DictionaryCalendar - a number system for long periods of time, based on periodic natural phenomena. Era - a system of chronology. Epoch - the starting point from accounts era.GOU secondary school Problem No. 4What is the main difficulty in creating any calendar system? Is there a difference in the days of the week in the old and new styles? How many years passed from the beginning of the hundredth year of our era to the beginning of the hundredth year of our era? summary Types of watches The simplest chronometric devices: sand, solar, floral, water, fire Mechanical watches: Mechanical, quartz, electronic Three main types of calendars Lunar - Arabic, Turkish Solar - Julian, Gregorian, Persian, Coptic Lunar-solar - Eastern, Central American GOU Secondary School No. 4 Problem 109 May in Minsk the clock shows 8:45. What time does the clock show in Berlin if at this time in European countries the clocks are switched to daylight saving time. What is the average standard time in Omsk at this moment? λ=4h 541, n = 5h. SolutionProblem 1 Let's write the ratio: Tl1- Tl2= n1- n2 Tl2= Tl1- (n1- n2)= 8h 451-1h=7h 451 the clock in Berlin shows2) more precisely: Tl1- Tl2= λ1- λ2. where λ1- λ2, the longitudes of cities Minsk and Brest. Solution to problem 2 From the relation Тλ1- Тλ2= λ1- λ2, we find Тλ2 = Тλ1- (λ1- λ2) by the formula.(1) From the relation Тn- Тλ=n- λ, we find Тn2= Тλ2+(n - λ) (2) Tλ2=6h 501-(8h 471-4h 541)= 6h 501-3h 541=2h 461Tn2=2h 461+(5h-4h 541)= 2h 461+0h61=2h 521Answer: average time Tλ=2h 461; and standard time Tn = 2 hours 521 Main conclusions The time interval between two successive culminations of the same name of the center of the solar disk on the same geographical meridian is called the true solar day. Due to the unevenness of the true solar day, average solar days are used in everyday life, the duration of which is constant. Sidereal day - the period of time between two successive culminations of the same name at the point of the vernal equinox on the same geographical meridian. The geographic longitude of a given area is determined by the difference between local and universal time. A calendar is a system for counting long periods of time, which is based on periodic astronomical phenomena. We live according to the Gregorian calendar.

Homework 1. Compare calendar systems: Gregorian and Julian. 2.§5, questions No. 1-11, page 39.

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The ancient Greek god of time Kronos The main property of time is that it lasts, flows non-stop. Time is irreversible - traveling to the past with a time machine is impossible. “You cannot enter the same river twice,” said Heraclitus. Ancient myths reflected the importance of time. Time is a continuous series of phenomena replacing each other.

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In ancient times, people determined time by the Sun. The ancient Indian observatory in Delhi, which also served as a sundial. The majestic Stonehenge is one of the oldest astronomical observatories, built five thousand years ago in Southern England. Already in those days they were able to determine time by the moment of sunrise. Solar calendar of the ancient Aztecs

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Thousands of years ago, people noticed that many things in nature repeat themselves: the Sun rises in the east and sets in the west, summer gives way to winter and vice versa. It was then that the first units of time arose - day, month and year. Using simple astronomical instruments, it was established that there are about 360 days in a year, and in approximately 30 days the silhouette of the Moon goes through a cycle from one full moon to the next. Therefore, the Chaldean sages adopted the sexagesimal number system as a basis: the day was divided into 12 night and 12 day hours, the circle - into 360 degrees. Every hour and every degree was divided into 60 minutes, and every minute into 60 seconds. The day is divided into 24 hours, each hour is divided into 60 minutes.

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Sundials are very diverse in shape. Since ancient times, time has been measured in days according to the time the Earth rotates around its axis.

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Subsequent more accurate measurements showed that the Earth makes a full revolution around the Sun in 365 days 5 hours 48 minutes and 46 seconds, i.e. for 365.25636 days. The Moon takes from 29.25 to 29.85 days to go around the Earth. The period of time between two culminations of the Sun is called a solar day. They begin at the moment of the lower culmination of the Sun on a given meridian (i.e. at midnight). Big Ben clock in London

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Solar days are not the same - due to the eccentricity of the earth's orbit, in the winter in the northern hemisphere the day lasts a little longer than in the summer, and in the southern hemisphere it is the other way around. In addition, the plane of the ecliptic is inclined to the plane of the earth's equator. Therefore, an average solar day of 24 hours was introduced. Greenwich. London Mean solar time, counted from midnight, on the Greenwich meridian is called universal time. Denoted by UT (Universal Time). Local time is convenient for everyday life - it is associated with the alternation of day and night in a given area. In an area with geographic longitude λ, local time (Tλ) will differ from universal time (To) by a number of hours, minutes and seconds equal to λ: Tλ = To + λ

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To eliminate discrepancies in the calculation of time in different settlements, it is customary to divide the earth's surface into time zones. 24 earth meridians were chosen (every 15 degrees). From each of these 24 meridians we measured 7.5° in both directions and drew the boundaries of time zones. Within time zones, time is the same everywhere. Zero zone – Greenwich. The Prime Meridian passes through the Greenwich Observatory, located near London.

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On each of these meridians, standard time differs from universal time by an integer number of hours equal to the zone number, and the minutes and seconds coincide with Greenwich Mean Time. In our country, standard time was introduced on July 1, 1919. There are 11 time zones across Russia (from II to XII inclusive).

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Knowing the universal time (To) and the zone number of a given place (n), you can easily find the standard time (Tp): Tp = To + n Prime meridian. Greenwich. London

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In 1930, all clocks in the former Soviet Union were moved forward an hour. And in March, Russians move their clocks forward another hour (that is, already 2 hours compared to standard time) and until the end of October they live according to summer time: Tl = Tp +2h

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Moscow time is local time in the capital of Russia, located in time zone II. According to Moscow winter time, true noon in Moscow occurs at 12 hours 30 minutes, according to summer time - at 13 hours 30 minutes.

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A calendar with leap years is called Julian. It was developed on behalf of Julius Caesar in 45 BC. The Julian calendar gives an error of one day every 128 years. The Gregorian calendar (the so-called new style) was introduced by Pope Gregory XIII. In accordance with a special bull, the count of days was moved forward 10 days. The next day after October 4, 1582 began to be considered October 15. The Gregorian calendar also has leap years, but it does not consider leap years for centuries in which the number of hundreds is not divisible by 4 without a remainder (1700, 1800, 1900, 2100, etc.). Such a system will give an error of one day in 3300 years. In our country, the Gregorian calendar was introduced in 1918. In accordance with the decree, the count of days was moved forward 13 days. The next day after January 31 began to be considered February 14. Currently, most countries in the world practice the Christian era. The counting of years begins from the Nativity of Christ. This date was introduced by the monk Dionysius in 525. All years before this date became known as “BC,” and all subsequent dates became “AD.”

INFORMATION SHEET

"CALENDARS"

Calendar - a system for calculating long periods of time, based on the periodicity of such natural phenomena as the change of day and night (day), change of phases of the Moon (month), change of seasons (year). Making calendars and keeping track of chronology has always been the responsibility of church ministers.

The choice of the beginning of chronology (establishing an era) is conditional and is most often associated with religious events - the creation of the World, the global flood, the birth of Christ, etc.

A month and a year do not contain an integer number of days; all these three measures of time are incommensurable, and it is impossible to simply express one of them through the other.

1. Moon calendar(homeland - Babylon). Currently exists in a number of Arab countries. The year consists of 12 lunar months of 29 or 30 days, the length of the year is 354 or 355 days.
2. Lunar-solar calendar(homeland - Ancient Greece). The year was divided into 12 months, each of which began with a new moon. To communicate with the seasons, an additional 13th month was periodically inserted. Currently, such a system is preserved in the Jewish calendar.
3. Solar calendar(homeland - Ancient Egypt). In Egypt, the summer solstice periods are associated with the first predawn rising of Sirius and coincide with the beginning of the Nile flood. Observations of the appearance of Sirius made it possible to determine the length of the year, which was accepted as 365 days. The year is divided into 12 months of 30 days each, with an additional 5 days added at the end of the year. The year is also divided into 3 seasons of 4 months each (the time of the Nile flood, the time of sowing, the time of harvest).
4. Roman solar calendar- known since the 8th century BC. The year first included 10 months and contained 304 days, then 2 more months were added, and the number of days was increased to 355. Every 2 years an additional month of 22-23 days was inserted. The average length of the year for 4 years was 366.25 days.
5. Julian calendar- Roman solar calendar, reformed in 46 BC. Roman statesman Julius Caesar. The counting began on January 1, 1945. BC. 3 years in a row contain 365 days and are called simple years, the 4th year - a leap year - contains 366 days. The average length of the year is 365.25 days. But for every 128 years, the spring equinox receded by 1 day, which by the 16th century led to a discrepancy of 10 days and greatly complicated the calculations of church holidays.
6. Gregorian calendar- a calendar corrected by decree of the head of the Catholic Church, Pope Gregory XIII. It was decided after Thursday October 4th 1582 skip 10 days in the year count and consider the next day to be Friday, October 15, and in the future follow the “leap year rule” - years ending in two zeros are considered leap years only if they are divisible by 400.

The Gregorian reform took place in the most difficult struggle. The great Copernicus refused to take part in its preparation, which began already in 1514. The Council of Trent (international conference), where issues of reform were considered, lasted, with interruptions, for 18 years, from 1545 to 1563.

1. In Ancient Rus' According to pagan customs, the year began in the spring. With the introduction of Christianity, the Orthodox Church adopted the Julian calendar and the era from the “creation of the world” (5508 BC). Since December 19, 7208 (1700), by decree of Peter I, chronology has been calculated from the birth of Christ.

Russia switched to the Gregorian calendar in 1918. February 1 began to be counted as February 14, since the discrepancy with the Julian calendar was already 13 days.

BASIC CONCEPTS AND TERMS,

used in studying the topic

1. Coordinates - numbers that indicate the position of a point on a surface. They are usually expressed in angular distances (degrees, radians, etc.). Coordinates are determined by latitude and longitude.
2. Latitude - a value determined astronomically - the height of the celestial pole (the North Star) above the horizon. One of the first static mathematical quantities used in astronomy. Astronomers were able to calculate latitude already in the 3rd century BC. The basis of the first star catalogs.
3. Points with the same latitudes form parallels . The zero parallel is the equator (the North Star at the equator is visible on the horizon).
4. Longitude - a quantity that cannot be determined only with the help of astronomical observations. Longitude is the difference in time at different meridians (in hourly angular distances). They learned to determine longitude quite confidently in the 2nd half of the 18th century, when mechanical watches and chronometers appeared.
5. Meridian - a line connecting the poles and passing through a given point. Since 1884, the zero meridian (mystical name - “Rose Line”) has been taken to be a line passing through the Greenwich Observatory (outskirts of London). Until 1884, the prime meridian passed the Paris Louvre and the Paris Observatory.

TIME UNITS

1. Year - the time interval between two passages of the Sun through the main points of the Ecliptic (autumn and spring equinoxes, summer and winter solstices) is 365.24 days.
2. Month - the period of time for a complete revolution of the Moon around the Earth (the complete period of changing phases of the Moon) is equal to 29.53 days.
3. A week - conditional division based on religious traditions.
4. Day - the period of time between two successive positions of the Sun (usually upper or lower culminations - noon or midnight) on the same geographical meridian.
5. Hour - a period of time equal to 1/24 of a day, the period of time between the positions of the sun on meridians with a distance of 15 0 .
6. Minute - 1/60th of an hour (degree)
7. Second - 1/60th of a minute, 1/86400th of the duration of a solar day, a constant unit of time in the International System of Measurements.

Basic terms related to time:

1. Universal Time - Time at the Greenwich Meridian
2. Moscow time - time on the meridian of Moscow
3. Local time - conventional time adopted for a given region
4. Standard time is a single conventional time between two meridians with a distance of 15 0 .
5. Winter time - time change 1 hour back compared to standard time.
6. Daylight Saving Time - Standard Time from April to October

HISTORICAL REFERENCE

about the date of “creation of the world”

It's good to know what's out there200 different versions « dates of the creation of the world."We will indicate only the main examples:

1. 5969 BC - Antiochian, according to Theophilus
2. 5508 BC - Byzantine or Constantinople
3. 5493 BC - Alexandria, era of Annian
4. 4004 BC - according to Asher, Jewish
5. 5872 BC - dating of 70 interpreters
6. 4700 BC - Samaritan
7. 3761 BC - Jewish
8. 3491 BC - dating according to Jerome
9. 5199 BC - dating according to Eusebius of Caesarea
10. 5500 BC - according to Hippolytus and Sextus Julius Africanus
11. 5551 BC - according to Augustine
12. 5515, as well as 5507 BC. - according to Theophilus

The amplitude of fluctuations of this date counting point considered fundamental for ancient chronology is 2100 years ( 21 century! ). This question is by no means scholastic! The fact is that a huge number of old documents date the events described in the years “from Adam” or “from the creation of the world.” Therefore, the existing thousand-year discrepancies in the choice of this starting point significantly affect the dating of many old documents.

Chronology ancient and medieval historyin the form in which we have it now, it was created in a series of fundamental works of the 16th - 17th centuries by Joseph Scaliger (1540-1609) and Dionysius Pentavius ​​(1583-1652). These chronologists first usedastronomical methodconfirming his version of the chronology of previous centuries, which gave it a “scientific” character. Over the next 300 years, the chronology was not revised, and for a person of our time, the very idea that historians follow an erroneous chronology seems absurd, since it contradicts an already established tradition.

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Measuring time

Slide 2

Time
World Zone Local Stellar Solar Maternity Summer

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World Time
The rotation of the Earth around its axis sets the universal time scale. The rotation of the Earth and the cycle of day and night determine the most natural unit of time - the day. A day is the period of time between successive upper culminations on a given meridian of one of three fixed points on the celestial sphere: the vernal equinox, the center of the visible disk of the Sun (the true Sun), or a fictitious point moving uniformly along the equator and called the “mean sun.” In accordance with this, there are sidereal, true solar or average solar days. The prime meridian for all time measurements since 1884 has been the meridian of the Greenwich Observatory, and the mean solar time at the Greenwich meridian is called UT (Universal Time). Universal time is determined from astronomical observations, which are carried out by special services at many observatories around the world.

Slide 4

In the astronomical calendar for a month, the moments of phenomena are given according to universal time To. The transition from one time counting system to another is carried out according to the formulas: To=Tm - L, Tп=To+n(h)=Tm+n(h) - L. In these formulas To is universal time; Tm - local mean solar time; Tp - standard time; n(h) - time zone number (in Russia, another 1 hour of maternity time is added to the time zone number); L is geographic longitude in time units, considered positive east of Greenwich.
About counting time for observations

Slide 5

Sidereal time
For astronomical observations, sidereal time s is used, which is related to the mean solar time Tm and to universal time To by the following relations: S=So+To+L+ 9.86c * (To), S=So+Tm+ 9.86c * (Tm -L ), Here So is sidereal time at Greenwich Mean Midnight (sidereal time on the Greenwich meridian at 0 universal time hours), and the values ​​(To) and (Tm -L) enclosed in brackets are expressed in hours and decimals of an hour. Since the products 9.86c * (To) and 9.86c * (Tm -L) do not exceed four minutes, they can be neglected in approximate calculations.

Slide 6

Moscow standard time
The standard time of the second time zone in which Moscow is located is called Moscow time and is designated Tm. The standard time of other points on the territory of the Russian Federation is obtained by adding to Moscow time an integer number of hours deltaT, which is equal to the difference between the time zone numbers of this point and the time zone of Moscow: T = Tm + deltaT.

Slide 7

Summer time
In the spring-summer period, summer time is introduced in a significant part of Russia and other countries, i.e., all clocks are moved forward one hour. The transfer is carried out at two o'clock in the morning on the last Sunday in March. At the beginning of the autumn-winter period, at three o'clock in the morning on the last Sunday in October, the clocks are again set back one hour: winter time is introduced. Thus, in the spring-summer period Tm=To+4h and T=Tm-L+4H+deltaT, in the autumn-winter period Tm=To+3h and T=Tm-L+ZCh+deltaT.

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From the history of time measurement
The day is divided into 24 hours, each hour is divided into 60 minutes. Thousands of years ago, people noticed that many things in nature repeat themselves: the Sun rises in the east and sets in the west, summer gives way to winter and vice versa. It was then that the first units of time arose - day, month and year.
Using simple astronomical instruments, it was established that there are about 360 days in a year, and in approximately 30 days the silhouette of the Moon goes through a cycle from one full moon to the next. Therefore, the Chaldean sages adopted the sexagesimal number system as a basis: the day was divided into 12 night and 12 day hours, the circle - into 360 degrees. Every hour and every degree was divided into 60 minutes, and every minute into 60 seconds. However, subsequent more accurate measurements hopelessly spoiled this perfection. It turned out that the Earth makes a full revolution around the Sun in 365 days, 5 hours, 48 ​​minutes and 46 seconds. The Moon takes from 29.25 to 29.85 days to go around the Earth.

Slide 9

Sidereal and solar days
Let's choose any star and fix its position in the sky. The star will appear in the same place in a day, more precisely in 23 hours and 56 minutes. A day measured relative to distant stars is called a sidereal day (to be very precise, a sidereal day is the period of time between two successive upper culminations of the vernal equinox). Where do the other 4 minutes go? The fact is that due to the movement of the Earth around the Sun, it shifts for an earthly observer against the background of stars by 1° per day. To “catch up” with him, the Earth needs these 4 minutes. The days associated with the apparent movement of the Sun around the Earth are called solar days. They begin at the moment of the lower culmination of the Sun on a given meridian (i.e. at midnight). Solar days are not the same - due to the eccentricity of the earth's orbit, in the winter in the northern hemisphere the day lasts a little longer than in the summer, and in the southern hemisphere it is the other way around. In addition, the plane of the ecliptic is inclined to the plane of the earth's equator. Therefore, an average solar day of 24 hours was introduced.

Slide 10

Due to the movement of the Earth around the Sun, it shifts for an observer on Earth against the background of stars by 1° per day. 4 minutes pass before the Earth “catches up” with him. So, the Earth makes one revolution around its axis in 23 hours 56 minutes. 24 hours – the average solar day – is the time the Earth rotates relative to the center of the Sun.

Slide 11

Prime Meridian
The Prime Meridian passes through the Greenwich Observatory, located near London. A person lives and works by a sundial. On the other hand, astronomers need sidereal time to organize observations. Each area has its own solar and sidereal time. In cities located on the same meridian, it is the same, but when moving along the parallel it will change. Local time is convenient for everyday life - it is associated with the alternation of day and night in a given area. However, many services, such as transport, must operate at the same time; So, all trains in Russia run according to Moscow time. To ensure that individual settlements do not end up in two time zones at once, the boundaries between the zones have been shifted slightly: they are drawn along the borders of states and regions.

Slide 12

To avoid confusion, the concept of Greenwich Time (UT) was introduced: this is the local time on the prime meridian on which the Greenwich Observatory is located. But it is inconvenient for Russians to live on the same time as Londoners; This is how the idea of ​​standard time came about. 24 earth meridians were chosen (every 15 degrees). At each of these meridians, time differs from universal time by an integer number of hours, and the minutes and seconds coincide with Greenwich Mean Time. From each of these meridians we measured 7.5° in both directions and drew the boundaries of time zones. Within time zones, time is the same everywhere. In our country, standard time was introduced on July 1, 1919.
In 1930, all clocks in the former Soviet Union were moved forward an hour. This is how maternity time appeared. And in March, Russians move their clocks forward another hour (i.e., already 2 hours compared to standard time) and live according to summer time until the end of October. This practice is accepted in many European countries.
Standard time
http://24timezones.com/map_ru.htm

Slide 13

Date line
Returning from the first circumnavigation of the world, Ferdinand Magellan's expedition found out that a whole day had been lost somewhere: according to ship time, it was Wednesday, and the local residents, one and all, claimed that it was already Thursday. There is no mistake in this - the travelers sailed all the time to the west, catching up with the Sun, and, as a result, saved 24 hours. A similar story happened with Russian explorers who met the British and French in Alaska. To solve this problem, the International Date Line agreement was adopted. It passes through the Bering Strait along the 180th meridian. On Kruzenshtern Island, which lies to the east, according to the calendar, one day less than on Rotmanov Island, which lies to the west of this line.

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Quiz questions
http://www.eduhmao.ru/info/1/3808/34844/ http://www.afportal.ru/astro/test

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1. The sidereal day, in contrast to the true solar day, has a constant duration. Why are they not used in public life?
Because: 1) it is more convenient to measure time using the movement across the sky of the most noticeable celestial body - the Sun, and not the vernal equinox point, which is not marked by anything in the sky; 2) using sidereal time in a year would result in 366 sidereal days with 365 quite noticeable days; 3) the sidereal day begins, at least at a given time, at different hours of the day and night; 4) when using any solar day, we can, to some extent, orient ourselves in time by the position of the Sun in the sky, but when using sidereal days, such orientation would be quite difficult and completely impossible for people new to astronomy.

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2. Why don’t people use solar time in everyday life now?
Because the duration of the true solar day continuously changes throughout the year, which could not be noticed in ancient times. It would be very difficult to make a clock that kept exactly true solar time, and, moreover, the interests of science and technology require the establishment of constant rather than variable units of time (in this case, the day).

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3. When in the year are there the longest and shortest true solar days? What is the difference between the two?
The longest true solar day occurs around December 23 - 24 hours 04 minutes 27 seconds, and the shortest - around September 16 - 24 hours 03 minutes 36 seconds. The difference between them is about 51 sidereal seconds.

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4. It is usually believed that along the entire length of any meridian, from pole to pole, there is the same hour of the day and that when moving along the meridian there is no need to rearrange the clock hands. Answer, is this really so?
No. Quite often the same meridian passes through different time zones. However, local sidereal time and local mean solar time are the same throughout the entire length of any one meridian.

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5. Assuming that the time for telephone conversations begins at 8 o'clock. and ends at 11 p.m. Standard time abroad and maternity time here, find the hours of the day convenient for telephone calls between London and New York using London standard time; between Moscow and Vladivostok according to Moscow maternity time.
From 1pm to 11pm inclusive London Standard Time. From 8 a.m. to 4 p.m. inclusive, Moscow maternity time.

Slide 20

6. The steamer left San Francisco on August 1 at 12 noon. And arrived in Vladivostok also at 12 noon. August 18. How many days did this flight last?
16 days
7. At what time, Moscow maternity time, does the New Year enter Russia?
At 2 p.m.
8. How long does any date, such as January 1, last on Earth?
Any calendar date is held on the globe for two days.

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9. Having learned that each date is delayed on Earth for two days, one student protested: “Excuse me, but then all our years would last for two years. That means something is wrong here.” What would you answer to this student?
In every place on Earth, any calendar date “lives” for only one day, and therefore the year has its usual duration.

It was developed on behalf of Julius Caesar in 45 BC. The Julian calendar gives an error of one day every 128 years. The Gregorian calendar (the so-called new style) was introduced by Pope Gregory XIII. In accordance with a special bull, the count of days was moved forward 10 days. The next day after October 4, 1582 began to be considered October 15. The Gregorian calendar also has leap years, but it does not consider leap years for centuries in which the number of hundreds is not divisible by 4 without a remainder (1700, 1800, 1900, 2100, etc.). Such a system will give an error of one day in 3300 years. In our country, the Gregorian calendar was introduced in 1918. In accordance with the decree, the count of days was moved forward 13 days. The next day after January 31 began to be considered February 14. Currently, most countries in the world practice the Christian era. The counting of years begins from the Nativity of Christ. This date was introduced by the monk Dionysius in 525. All years before this date became known as “BC,” and all subsequent dates became “AD.”