Time and calendar. Exact time and determination of geographic longitude. Presentation - measuring time Basics of measuring time in astronomy presentation

The material is intended to be studied within additional education or extracurricular activities in astronomy by students in grades 7-8. The concepts of sidereal and solar time, zone time and maternity time are considered.

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Measuring time © Bogdanova Irina Viktorovna 2012-2013

From the history of time measurement Thousands of years ago, people noticed that much in nature repeats itself: 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. The day is divided into 24 hours, each hour is divided into 60 minutes. 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.

Sidereal and solar time The rotation of the Earth around its axis sets the 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 is considered to be 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 carried out by special services at many observatories around the world. The Prime Meridian passes through the Greenwich Observatory, located near London. World Time

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: Here So is sidereal time at Greenwich Mean Midnight (sidereal time at the Greenwich meridian at 0 o'clock universal time), and those enclosed in brackets values ​​(To) and (Tm - λ) are expressed in hours and decimals of an hour. Since the products 9.86c * (To) and 9.86c * (Tm - λ) do not exceed four minutes, they can be neglected in approximate calculations. S = So+To +λ + 9.86c * (To) S = So+Tm + 9.86c * (Tm – λ)

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. 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. A day measured relative to distant stars is called a stellar day. The days associated with the apparent movement of the Sun around the Earth are called solar days.

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.

Each locality has its own solar and sidereal time. A person lives and works by a sundial. On the other hand, astronomers need sidereal time to organize observations. In cities located on the same meridian, it is the same, but when moving along the parallel it will change. Local time 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.

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: About time counting for observations In these formulas That 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); λ is geographic longitude in time units, considered positive east of Greenwich. To= Tm - λ Tp = To+n (h)= Tm+n (h) - λ

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 selected (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, on the territory of the former Soviet Union all clocks were set forward an hour. This is how maternity time appeared. Standard time

Moscow zone time The zone 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 ΔT, which is equal to the difference between the time zone numbers of this point and the time zone of Moscow: T = Tm + ΔT.

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.

Sources of information http://24timezones.com/map_ru.htm http://www.astronet.ru/db/msg/1175352/node10. html http://topography.ltsu.org/zz/leksii/ zz10_vremya.pdf http://www.astrogalaxy.ru/027. html

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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 " high school No. 4, 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 Plan 1 . 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 into the past with a time machine is impossible. “You cannot enter the same river twice,” said Heraclitus. Ancient myths reflected the importance of time. The basic unit of time is the day, month, year. The basic value of measuring time is related to the period of rotation globe around its axis of circulation Time is a continuous series of phenomena replacing each other. 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 (that is, already 2 hours compared to standard time) and until the end of October they live according to summer time: Tl = Tp +2h Moscow time- this is local time in the capital of Russia, located in time zone II. According to Moscow winter time, true noon in Moscow occurs at 12:30 a.m., in summer time - at 1:30 p.m. 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 miners ancient world, were 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. Further development calendar systems occurred through the development of permanent (“perpetual”) calendars. Currently, permanent calendars of a wide variety of devices are known, compiled for both short and long periods of time, allowing one to determine the day of the week of any calendar date of the Julian or Gregorian calendar or both at once - universal calendars. 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 days name number of daysMarch 31 September 29 April 29 October 31 May 31 November 29 June 29 December 29 Quintilis 31 January 29 Sextilis 29 February 28 Dictionary Calendar - a number system for long periods of time, based on periodic natural phenomena. Era - a chronology system. Epoch - the starting point of reference 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) according to 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.

Lesson 6

Astronomy lesson topic: Basics of time measurement.

Progress of an astronomy lesson in 11th grade

1. Repetition of what has been learned

a) 3 people on individual cards.

• 1. At what altitude in Novosibirsk (?= 55?) does the Sun culminate on September 21?
• 2. Where on earth are no stars of the southern hemisphere visible?

• 1. The midday altitude of the Sun is 30?, and its declination is 19?. Determine the geographic latitude of the observation site.
• 2. How are the daily paths of the stars located relative to the celestial equator?

• 1. What is the declination of the star if it culminates in Moscow (?= 56?) at an altitude of 69??
• 2. How is the axis of the world located relative to the earth’s axis, relative to the horizon plane?

b) 3 people at the board.

1. Derive the formula for the height of the luminary.

2. Daily paths of luminaries (stars) at different latitudes.

3. Prove that the height of the celestial pole is equal to the geographic latitude.

c) The rest on their own.

• 1. Which one greatest height reaches Vega (?=38о47") in Cradle (?=54о05")?
• 2. Select any bright star using PCZN and write down its coordinates.
• 3. In what constellation is the Sun today and what are its coordinates?

d) in "Red Shift 5.1"

Find the Sun:

What information can you get about the Sun?

What are its coordinates today and what constellation is it in?

How does declination change?

Which of the stars has given name, is closest in angular distance to the Sun and what are its coordinates?

Prove that the Earth is currently moving in orbit closer to the Sun

2. New material

Students need to pay attention to:

1. The length of the day and year depends on the reference system in which the Earth’s movement is considered (whether it is connected with the fixed stars, the Sun, etc.). The choice of reference system is reflected in the name of the time unit.

2. The duration of time units is related to the visibility conditions (culminations) of celestial bodies.

3. The introduction of the atomic time standard in science was due to the uneven rotation of the Earth, discovered when the accuracy of clocks increased.

4. The introduction of standard time is due to the need to coordinate economic activities in the territory defined by the boundaries of time zones.

Time counting systems.

Relationship with geographic longitude. Thousands of years ago, people noticed that many things in nature were repeated. It was then that the first units of time arose - day, month, 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.

Periodic phenomena accompanied by the daily rotation of the celestial sphere and the apparent annual movement of the Sun along the ecliptic underlie various time counting systems. Time is the main thing

a physical quantity that characterizes the successive change of phenomena and states of matter, the duration of their existence.

Short - day, hour, minute, second

Long - year, quarter, month, week.

1. "Star" time, associated with the movement of stars on the celestial sphere. It is measured by the hour angle of the vernal equinox.

2. "Sunny" time, associated: with the visible movement of the center of the solar disk along the ecliptic (true solar time) or the movement of the “average Sun” - an imaginary point moving uniformly along the celestial equator in the same period of time as the true Sun (average solar time).

With the introduction of the atomic time standard and the International SI System in 1967, physics has used atomic second.

Second is a physical quantity numerically equal to 9192631770 periods of radiation corresponding to the transition between hyperfine levels of the ground state of the cesium-133 atom.

In everyday life, mean solar time is used. The basic unit of sidereal, true and mean solar time is the day. We obtain sidereal, mean solar and other seconds by dividing the corresponding day by 86400 (24h, 60m, 60s). The day became the first unit of time measurement over 50,000 years ago.

Sidereal day- this is the period of rotation of the Earth around its axis relative to the fixed stars, defined as the period of time between two successive upper culminations of the vernal equinox.

True solar days- this is the period of rotation of the Earth around its axis relative to the center of the solar disk, defined as the time interval between two successive culminations of the same name at the center of the solar disk.

Due to the fact that the ecliptic is inclined to the celestial equator at an angle of 23°26", and the Earth rotates around the Sun in an elliptical (slightly elongated) orbit, the speed of the apparent movement of the Sun across the celestial sphere and, therefore, the duration of the true solar day will constantly change throughout the year: the most fast near the equinox points (March, September), slowest near the solstices (June, January).To simplify time calculations, the concept of the average solar day was introduced in astronomy - the period of rotation of the Earth around its axis relative to the “average Sun”.

The average solar day is defined as the time interval between two successive culminations of the same name of the “average Sun”. They are 3m55,009s shorter than a sidereal day.

24h00m00s sidereal time is equal to 23h56m4.09s mean solar time. For the certainty of theoretical calculations, an ephemeris (tabular) second was adopted equal to the average solar second on January 0, 1900 at 12 o'clock equal current time, not associated with the rotation of the Earth.

About 35,000 years ago, people noticed the periodic change in the appearance of the Moon - the change of lunar phases. Phase Ф of a celestial body (Moon, planet, etc.) is determined by the ratio of the largest width of the illuminated part of the disk d to its diameter D: Ф=d/D. The terminator line separates the dark and light parts of the luminary's disk. The Moon moves around the Earth in the same direction in which the Earth rotates around its axis: from west to east. This movement is reflected in the visible movement of the Moon against the background of stars towards the rotation of the sky. Every day, the Moon moves east by 13.5o relative to the stars and completes a full circle in 27.3 days. This is how the second measure of time after the day was established - the month.

A sidereal (sidereal) lunar month is the period of time during which the Moon makes one full revolution around the Earth relative to the fixed stars. Equal to 27d07h43m11.47s.

A synodic (calendar) lunar month is the period of time between two successive phases of the same name (usually new moons) of the Moon. Equal to 29d12h44m2.78s.

The combination of the phenomena of the visible movement of the Moon against the background of stars and the changing phases of the Moon allows one to navigate by the Moon on the ground (Fig.). The moon appears as a narrow crescent in the west and disappears in the rays of dawn as an equally narrow crescent in the east. Let's mentally draw a straight line to the left of the lunar crescent. We can read in the sky either the letter “R” - “growing”, the “horns” of the month are turned to the left - the month is visible in the west; or the letter “C” - “aging”, the “horns” of the month are turned to the right - the month is visible in the east. During a full moon, the moon is visible in the south at midnight.

As a result of observations of changes in the position of the Sun above the horizon for many months, arose third measure of time - year.

Year- this is the period of time during which the Earth makes one full revolution around the Sun relative to some landmark (point).

Sidereal year - this is the sidereal (stellar) period of the Earth’s revolution around the Sun, equal to 365.256320... average solar days.

Anomalistic year- this is the time interval between two successive passages of the average Sun through a point in its orbit (usually perihelion), equal to 365.259641... average solar day.

Tropical year- this is the time interval between two consecutive passages of the average Sun through the vernal equinox, equal to 365.2422... average solar days or 365d05h48m46.1s.

Universal time is defined as the local mean solar time at the prime (Greenwich) meridian (To, UT - Universal Time). Since in everyday life local time cannot be used (since in Kolybelka it is one, and in Novosibirsk it is different (different?)), therefore it was approved by the Conference at the proposal of the Canadian railway engineer Sanford Fleming (February 8, 1879, during a speech at the Canadian Institute in Toronto) standard time, dividing the globe into 24 time zones (360:24 = 15°, 7.5° from the central meridian). The zero time zone is located symmetrically relative to the prime (Greenwich) meridian. The belts are numbered from 0 to 23 from west to east. The real boundaries of the belts are combined with the administrative boundaries of districts, regions or states. The central meridians of time zones are separated from each other by exactly 15 degrees (1 hour), therefore, when moving from one time zone to another, the time changes by an integer number of hours, but the number of minutes and seconds does not change. New calendar day (and New Year) begin on the date line (demarcation line), which runs mainly along the meridian of 180° east longitude near the northeastern border of the Russian Federation. West of the date line, the date of the month is always one more than east of it. When crossing this line from west to east, the calendar number decreases by one, and when crossing the line from east to west, the calendar number increases by one, which eliminates the error in counting time when traveling around the world and moving people from the Eastern to the Western hemispheres of the Earth.

Therefore, the International Meridian Conference (1884, Washington, USA) in connection with the development of telegraph and railway transport introduced:

The day begins at midnight, and not at noon, as it was.

The prime (zero) meridian from Greenwich (Greenwich Observatory near London, founded by J. Flamsteed in 1675, through the axis of the observatory telescope).

Time counting system

Standard time is determined by the formula: Tn = T0 + n, where T0 is universal time; n - time zone number.

Maternity time is standard time changed to an integer number of hours by government regulation. For Russia it is equal to zone time, plus 1 hour.

Moscow time- this is maternity time of the second time zone (plus 1 hour): Tm = T0 + 3 (hours).

Summer time- maternity standard time, changed additionally by plus 1 hour by government order for the period of summer time in order to save energy resources. Following the example of England, which introduced daylight saving time for the first time in 1908, there are now 120 countries around the world, including Russian Federation makes the annual transition to daylight saving time.

Next, you should briefly introduce students to astronomical methods for determining geographical coordinates(longitude) of the area. Due to the rotation of the Earth, the difference between the moments of the onset of noon or the culmination (culmination. What is this phenomenon?) of stars with known equatorial coordinates at 2 points is equal to the difference in the geographical longitudes of the points, which makes it possible to determine the longitude of a given point from astronomical observations of the Sun and other luminaries and, vice versa , local time at any point with a known longitude.

For example: one of you is in Novosibirsk, the second is in Omsk (Moscow). Which of you will observe the upper culmination of the center of the Sun first? And why? (note, this means that your watch runs according to Novosibirsk time). Conclusion - depending on the location on Earth (meridian - geographic longitude), the culmination of any star is observed in different time, that is, time is related to geographic longitude or T= UT+?, and the time difference for two points located on different meridians will be T1-T2=?1-?2. The geographic longitude (?) of the area is measured east of the “zero” (Greenwich) meridian and is numerically equal to the time interval between the same climaxes of the same star on the Greenwich meridian (UT) and at the observation point (T). Expressed in degrees or hours, minutes and seconds. To determine the geographic longitude of an area, it is necessary to determine the moment of culmination of a luminary (usually the Sun) with known equatorial coordinates. By converting the observation time from mean solar to sidereal using special tables or a calculator and knowing from the reference book the time of the culmination of this star on the Greenwich meridian, we can easily determine the longitude of the area. The only difficulty in calculations is the exact conversion of time units from one system to another. There is no need to “watch” the moment of culmination: it is enough to determine the height (zenith distance) of the luminary at any precisely recorded moment in time, but the calculations will then be quite complicated.

Clocks are used to measure time. From the simplest, used in ancient times, there is a gnomon - a vertical pole in the center of a horizontal platform with divisions, then sand, water (clepsydra) and fire, to mechanical, electronic and atomic. An even more accurate atomic (optical) time standard was created in the USSR in 1978. An error of 1 second occurs once every 10,000,000 years!

Time keeping system in our country.

2) Established in 1930 Moscow (maternity) time 2nd time zone in which Moscow is located, moving one hour forward compared to standard time (+3 to World Time or +2 to Central European Time). Canceled in February 1991 and reinstated again in January 1992.

3) The same Decree of 1930 abolished the daylight saving time (DST) in force since 1917 (April 20 and return on September 20), first introduced in England in 1908.

4) In 1981, the country resumed daylight saving time.

5) In 1992, by Decree of the President, maternity time (Moscow) time was restored from January 19, 1992, with the preservation of summer time on the last Sunday in March at 2 a.m. an hour ahead, and for winter time on the last Sunday in September at 3 o'clock in the morning an hour ago.

6) In 1996, by Decree of the Government of the Russian Federation No. 511 of April 23, 1996, summer time was extended by one month and now ends on the last Sunday of October. The Novosibirsk region is transferred from the 6th time zone to the 5th.

So, for our country in winter T= UT+n+1h, and in summer T= UT+n+2h

3. Accurate time service.

To accurately count time, a standard is needed, due to the uneven movement of the Earth along the ecliptic. In October 1967 in Paris, the 13th General Conference of the International Committee of Weights and Measures determines the duration of the atomic second - the period of time during which 9,192,631,770 oscillations occur, corresponding to the frequency of healing (absorption) of the Cesium atom - 133. The accuracy of atomic clocks is an error of 1 s per 10,000 years.

On January 1, 1972, the USSR and many countries of the world switched to the atomic time standard. Precise time signals broadcast over the radio are transmitted via atomic clocks to precise definition local time (i.e. geographic longitude - the location of reference points, finding the moments of the culmination of the stars), as well as for aviation and maritime navigation.

4. Years, calendar.

RECORDING is a system for calculating large periods of time. In many chronology systems, counting was carried out from some historical or legendary event.

Modern chronology - “our era”, “new era” (AD), “era from the Nativity of Christ” (R.H.), Anno Domeni (A.D. - “year of the Lord”) - is based on an arbitrarily chosen date of birth of Jesus Christ. Since it is not indicated in any historical document, and the Gospels contradict each other, the learned monk Dionysius the Small in 278 of the era of Diocletian decided to “scientifically”, based on astronomical data, calculate the date of the era. The calculation was based on: a 28-year "solar circle" - a period of time during which the numbers of months fall on exactly the same days of the week, and a 19-year "lunar circle" - a period of time during which the same phases of the Moon fall on the same days. the same days of the month. The product of the cycles of the “solar” and “lunar” circles, adjusted for the 30-year life of Christ (28 x 19 + 30 = 572), gave the starting date of modern chronology. Counting years according to the era “from the Nativity of Christ” “took root” very slowly: until the 15th century (i.e. even 1000 years later) in official documents Western Europe 2 dates were indicated: from the creation of the world and from the Nativity of Christ (A.D). Now this chronology system (new era) is accepted in most countries.

The starting date and subsequent calendar system are called an era. The starting point of an era is called its epoch. Among the peoples professing Islam, the chronology dates from 622 AD. (from the date of the resettlement of Muhammad, the founder of Islam, to Medina).

In Rus', the chronology “From the creation of the world” (“Old Russian era”) was carried out from March 1, 5508 BC until 1700.

CALENDAR (lat. calendarium - debt book; in Ancient Rome debtors paid interest on the day of the calendar - the first day of the month) - a number system for large periods of time, based on the periodicity of the visible movements of celestial bodies.

There are three main types of calendars:

1. Lunar calendar, which is based on a synodic lunar month with a duration of 29.5 average solar days. Originated over 30,000 years ago. The lunar year of the calendar contains 354 (355) days (11.25 days shorter than the solar one) and is divided into 12 months of 30 (odd) and 29 (even) days each (Muslim, Turkish, etc.). The lunar calendar is adopted as a religious and state calendar in the Muslim states of Afghanistan, Iraq, Iran, Pakistan, the United Arab Republic and others. Solar and lunisolar calendars are used in parallel for planning and regulating economic activities.

2. Solar calendar, which is based on the tropical year. Originated over 6000 years ago. Currently accepted as the world calendar. For example, the "old style" Julian solar calendar contains 365.25 days. Developed by the Alexandrian astronomer Sosigenes, introduced by Emperor Julius Caesar in Ancient Rome in 46 BC and then spread throughout the world. In Rus' it was adopted in 988 NE. In the Julian calendar, the length of the year is determined to be 365.25 days; three “simple” years have 365 days each, one leap year has 366 days. There are 12 months in a year of 30 and 31 days each (except February). The Julian year lags behind the tropical year by 11 minutes 13.9 seconds per year. The error per day accumulated over 128.2 years. Over 1500 years of its use, an error of 10 days has accumulated.

In the "new style" Gregorian solar calendar The length of the year is 365.242500 days (26 seconds longer than the tropical year). In 1582, the Julian calendar, by order of Pope Gregory XIII, was reformed in accordance with the project of the Italian mathematician Luigi Lilio Garalli (1520-1576). The counting of days was moved forward by 10 days and it was agreed that every century that is not divisible by 4 without a remainder: 1700, 1800, 1900, 2100, etc. should not be considered a leap year. This corrects an error of 3 days every 400 years. An error of 1 day “accumulates” in 3323 years. New centuries and millennia begin on January 1 of the “first” year of a given century and millennium: thus, the 21st century and the 3rd millennium AD (AD) began on January 1, 2001 according to the Gregorian calendar.

In our country, before the revolution, the Julian calendar of the “old style” was used, the error of which by 1917 was 13 days. On February 14, 1918, the world-accepted “new style” Gregorian calendar was introduced in the country and all dates moved forward 13 days. The difference between the old and new styles is 18 to 11 days, 19 to 12 days and 20 to 13 days (last until 2100).

Other types of solar calendars are:

Persian calendar, which determined the length of the tropical year at 365.24242 days; The 33-year cycle includes 25 “simple” years and 8 “leap” years. Much more accurate than the Gregorian: an error of 1 year “accumulates” in 4500 years. Developed by Omar Khayyam in 1079; was used in Persia and a number of other states until the mid-19th century.

Coptic calendar similar to the Julian: there are 12 months of 30 days in a year; after the 12th month in a “simple” year, 5 are added, in a “leap” year - 6 additional days. Used in Ethiopia and some other states (Egypt, Sudan, Turkey, etc.) in the territory of Copts.

3. Lunar-solar calendar, in which the movement of the Moon is coordinated with the annual movement of the Sun. The year consists of 12 lunar months of 29 and 30 days each, to which “leap” years containing an additional 13th month are periodically added to take into account the movement of the Sun. As a result, “simple” years last 353, 354, 355 days, and “leap” years last 383, 384 or 385 days. It arose at the beginning of the 1st millennium BC and was used in Ancient China, India, Babylon, Judea, Greece, and Rome. Currently adopted in Israel (the beginning of the year falls on different days between September 6 and October 5) and is used, along with the state one, in the countries of Southeast Asia (Vietnam, China, etc.).

All calendars are inconvenient because there is no consistency between the date and day of the week. The question arises of how to come up with a permanent world calendar. This issue is being resolved at the UN and, if adopted, such a calendar can be introduced when January 1 falls on a Sunday.

Fixing the material

1. Example 2, page 28

2. Isaac Newton was born on January 4, 1643 according to the new style. What is his date of birth according to the old style?

3. Longitude of the Cradle?=79o09" or 5h16m36s. Find the local time for the Cradle and compare it with the time in which we live.

Result:

• 1) What calendar do we use?
• 2) How does the old style differ from the new?
• 3) What is universal time?
• 4) What are noon, midnight, true solar days?
• 5) What explains the introduction of standard time?
• 6) How to determine standard time, local time?
• 7) Grades

Homework for astronomy lesson:§6; questions and tasks for self-control (page 29); page 29 “What to know” - main thoughts, repeat the entire chapter “Introduction to Astronomy”, Test No. 1 (if it is not possible to conduct it as a separate lesson).

1. Compose a crossword puzzle using the material studied in the first section.

2. Prepare a report on one of the calendars.

3. Compose a questionnaire based on the material in the first section (at least 20 questions, answers in brackets).

End of astronomy lesson

Slide 2

Ancient Greek god of time Kronos

• The main property of time is that it lasts, flows non-stop.
• Time is irreversible—traveling into 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.