time and calendar :e-book

8/14/2019 Time and Calendar :e-book

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e-book (for free circulation)

Origin of Time

& Calendar

By

Tamarapu Sampath Kumaran


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About the Author:

Mr T Sampath Kumaran is a freelance writer. He regularly contributesarticles on Management, Business, Ancient Temples, and Temple

Architecture to many leading Dailies and Magazines.

His articles are popular in The Young World section of THE HINDU

His e-books on nature, environment and different cultures of people around

the world are educative and of special interest to the young.

He was associated in the renovation and production of two Documentary

films on Nava Tirupathi Temples, and Tirukkurungudi Temple inTamilnadu.

Acknowledgement:

I wish to express my gratitude to the authors from whose works I gathered

the details for this book, and Courtesy, Google for some of the photographs.

Tamarapu Sampath Kumaran


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Time & Calendar

Celestial bodies, the sun, moon, planets, and stars have provided us a

reference for measuring the passage of time throughout our existence.

Ancient civilizations relied upon the apparent motion of these bodies

through the sky to determine seasons, months, and years.

Earth spins on its axis. As it spins around we get daylight and darkness. This

pattern of daylight and darkness repeats itself each time the earth completes

a full turn on its axis. Since different parts of the earth face the sun atdifferent times, there are different day times on earth. One day is based on

this repeating pattern of the spin of the earth.

The moon orbits the earth. Its appearance in the sky, viewed from earth

changes from one day to the other. This pattern repeats itself each time the

moon passes in its orbit between the sun and earth. One month is based on

this repeating pattern. The word month comes from moon and both arebelieved to come from the same Indo-European root word which means to


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measure. The waning and waxing of the moon is calculated to be about

twenty nine or thirty days from one new moon to the other.

Like the Moon, Earth orbits the sun. As it goes on its orbit around the sun

we pass from one season to the next. The pattern of the seasons repeats itself

each time earth starts a new orbit. One year is based on this repeating

pattern.

The system of dividing the day and night into twenty-four parts comes from

the Egyptians. At first they divided the night into twelve parts, each marked

by the appearance of a particular star or constellation on the Eastern horizon.

The hours of the day were numbered from one to ten according to the

position of the Sun, the twilight hours one at the dawn and another at dusk

were at first reckoned separately, and eventually they were counted with the

daylight hours.

The day is divided into 24 smaller parts called hours, as 12 hours of day time

and 12 hours of night time. Each hour is divided into 60 minutes and again

to 60 seconds a minute.

Babylonian Calendar

The earliest Egyptian calendar was based on the moon's cycles, but later theEgyptians realized that the "Dog Star" in Canis Major, which is now called

Sirius, rose next to the sun every 365 days, about the time, when the annualinundation of the Nile began. Based on this knowledge, they devised a 365-

day calendar.


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One year is also linked to the season. The pattern of the seasons repeats itself

in just about 365-1/4 day. Because it is not a whole number of days one

calendar year is calculated as 365 days. Once in four years it is calculated as

366 days and the year is called leap year. The year is again divided into 12

months, and this extra day is added to the month of February during the leap

year.

During, 45 BC the Roman emperor Julius Caesar introduced the Julian

calendar, beginning with March.

Julius Caesar Pope Grerory XIII


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Our calendar being followed till date is called Gregorian calendar worked

out later by Pope Gregory XIII., starting the months from January.

The Romans who started the calendar named the months.

January was named after Roman God Janus.

February after the Roman festival Februa.

March after Mars the Roman God of war.

Aprilafter the Latin word APERIRE, which means open. In Rome manyflower buds started to appear in April.


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May after the Roman Goddess of growth Maia, since springis the time of growth

June after the Goddess of marriage, Juno.

July in honour of Julius Caesar.

Augustafter Roman emperor Augustus.

September, October, November and Decembercomes from the Latin words

meaning seventh, eighth, ninth and tenth months of the year, based on the

year beginning with March.


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Though the lengths of a month and of a year were roughly governed by the

moon and the sun, the week had seven days by chance. The week was kept

as seven days as each day was devoted to the worship of a different heavenly

body. The names of the day in a week come from Roman names after Sun,

Moon and the planets Mars, Mercury, Jupiter, Venus and Saturn. Later the

four names have been changed as Tuesday afterTIUthe God of war and

justice. Wednesday, was named after God Woden, Thursday, after God Thor

and Friday after GoddessFrigg.

Hindus Muslims, Jews and Buddhists have their own calendars.

Many religions and tribes have their own calendars depending on their faith.

Hindu calendar used in ancient times has undergone many changes in the

process of regionalization, and today there are several regional Indian

calendars. Most of these calendars are inherited from a system firstenunciated in Vedas, standardised in Surya Sidhanta, which was

subsequently reformed by astronomers Aryabhatta, Varahamihira and

Bhaskara. Hindu calendar is based on the movement of Moon. A lunar

month has 30 lunar days and is measured from new Moon to the next new

Moon. Each Lunar day is called a Tithi. There are 15 Tithis in the dark and

15 in the bright half of the month

The Islamic calendar or Muslim calendar also called Hijri calendar is based

on 12 lunar months in a year of 354 or 355 days, and used by Muslims

everywhere to determine the proper day on which to celebrate Islamic holydays and festivals. The first year was the year during which the Hijra the

emigration of Prophet Mohammed from Mecca to Medina occurred. The

Moslem calendar months travel through the seasons. Rabia I and Rabia II

mean the first and second spring months, and Ramadan comes during the hot

months.

The Hebrew calendar or Jewish calendar is used by Jews to reckon the

Jewish New Year and dates for Jewish holidays. The principles of the

Hebrew calendar are found in the Torah which contains several calendar-related commandments, including God's commandment during the exodusfrom Egypt to fix the month ofNisan as the first month of the year, in the

6th century, including the adoption of Babylonian names for the months

The Buddhist calendar is used in the mainland of Southeast Asian countries

and Sri Lanka, having months that are alternately 29 and 30 days, with an


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intercalated day and a 30-day month added at regular intervals. All of its

forms are based on the original 3rd-century Surya Siddhanta.

Quest to determine time:

With the need for knowing the time of day, the Egyptians formally divided

their day into parts something like our hours. They built a slender, tapering;

four-sided monument called Obelisks. During the day the moving shadowswithin, formed a kind of sundial enabling citizens to partition the day into

two parts by indicating noon. They also showed the year's longest and

shortest days when the shadow at noon was the shortest or longest of the

year. Later, markers were added around the base of the monument to

indicate further time subdivisions.

In the quest for more year-round accuracy, Greeks and Romans adoptedfrom the Egyptians the sundials which were more elaborate in the

construction. One version was the hemispherical dial, a bowl-shaped

depression cut into a block of stone, carrying a central vertical pointer and

scribed with sets of hour lines for different seasons.

Possibly the first portable timepiece - Egyptian shadow clock or sundial -

came into use around 1500 B.C. to measure the passage of "hours."

This device divided a sunlit day into 10 parts plus two "twilight hours" in themorning and evening. When the long stem with 5 variably spaced marks was

oriented east and west in the morning, an elevated crossbar on the east end

cast a moving shadow over the marks. At noon, the device was turned in the

opposite direction to measure the afternoon "hours." Wealthy people used

portable sundial.


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Water clocks were among the earliest timekeepers that did not depend on the

observation of celestial bodies. Greeks, who began using them about 325

B.C., were stone vessels with sloping sides that allowed water to drip at a

nearly constant rate from a small hole near the bottom. Other clepsydraswere cylindrical or bowl-shaped containers designed to slowly fill with

water coming in at a constant rate. Markings on the inside surfaces measured

the passage of "hours" as the water level reached them. These clocks were

mainly used to determine hours at night, besides daytime. Another version

consisted of a metal bowl with a hole in the bottom; when placed in a

container of water the bowl would fill and sink in a certain time. These are

still in use in North Africa.

More elaborate and impressive mechanized water clocks were developed

between 100 B.C. and 500 A.D. by Greek and Roman horologists and

astronomers. Since the rate of flow of water is very difficult to control

accurately, a clock based on that flow could never achieve excellent

accuracy. This naturally led people to other approaches.

During 1510 AD, Peter Henlein, a German locksmith from Nuremberg

invented a spring-powered clock nicknamed "Nuremberg Eggs".

In 1656, Christian Huygens, a Dutch scientist, made the first pendulum

clock, regulated by a mechanism with a "natural" period of oscillation.Huygens' pendulum clock had an error of less than 10 seconds a day. And in

London in 1671 William Clement began building clocks with the new

"anchor" or "recoil" escapement, a substantial improvement over the verge

because it interferes less with the motion of the pendulum.


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The word clock comes from the Latin Clocca through French Clochemeaning a bell. Bells were very important in the life of mediaeval towns-

people. They rang the hours shown by sundials. They told people when to

get up, when to go to bed, and when to go for prayers.

The worlds first mechanical clock was made in Europe around 700 years

ago. Around 1675, Huygens developed the balance wheel and spring

assembly, still found in some of today's wrist watches.

Over the next century refinements led in 1889 to Siegmund Riefler's clock

with a nearly free pendulum, which attained an accuracy of a hundredth of a

second a day and became the standard in many astronomical observatories.


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A true free-pendulum principle was introduced by R. J. Rudd about 1898,

stimulating development of several free-pendulum clocks. One of the most

famous, the W. H. Shortt clock, was demonstrated in 1921. The Shortt clock

almost immediately replaced Riefler's clock as a supreme timekeeper in

many observatories.

To facilitate people to carry the watch with them, wrist watches were

developed. Clocks which started out quite simply had more complicated

additions made later. Clocks which needed winding were later converted to

automatic electric winding.

The Shortt clock was replaced as the standard by quartz crystal clocks in the1930s and 1940s, improving timekeeping performance far beyond that of

pendulum and balance-wheel escapements. Quartz clock operation is based

on the piezoelectric property of quartz crystals. Such quartz clocks continue

to dominate the market in numbers because their performance is excellent

and they are inexpensive. But the timekeeping performance of quartz clocks

has been substantially surpassed by atomic clocks

Scientists had long realized that atoms (and molecules) have resonances;

each chemical element and compound absorbs and emits electromagneticradiation at its own characteristic frequencies. These resonances are

inherently stable over time.

In the 1840s, a Greenwich standard time for all of England, Scotland, and

Wales was established, replacing several "local time" systems. The Royal

Greenwich Observatory was the focal point for this development because it


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had played such a key role in marine navigation based upon accurate

timekeeping. Greenwich Mean Time (GMT) subsequently evolved as the

official time reference for the world.

Timekeeping had to reflect changes in the earth's rotation rate; otherwisenavigators would make errors. Thus, improvements were made providing

time linked to "earth" time, and other services, including almanacs,

necessary for sea and air navigation.

With the advent of highly accurate atomic clocks, scientists and

technologists recognized the inadequacy of timekeeping based on the motion

of the earth which fluctuates in rate by a few thousandths of a second a day.

A compromise time scale was eventually devised, and on January 1, 1972,

the new Coordinated Universal Time (UTC) became effectiveinternationally.

The World's Time Zones

On November 1, 1884, the International Meridian Conference in

Washington, DC, applied zones all around the world. The 24 standard

meridians, every 15 east and west of 0 at Greenwich, England, weredesignated the centers of the zones.


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The position of the needles in a watch in all advertisements is shown as 10 10 (ten past ten TPT). Most significant one being the visibility point of

view, which allows the viewer have an uninterrupted view of the face of the

clock. This allows the logo or emblem and the name of the manufacturer to

be fully visible too.

.


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