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Helpful information

Prime Meridian

Longitude Zero

Agreeing on a universal Prime Meridian was not an easy affair.

Oxford Time

What is Oxford Time?

Before the coming of the railways (railroad) every town had its local time.  With the introduction of Railway Time , time zones and Standard Time became the norm.

Time is money?

From Plot Device to Philosophy : Shakespeare and Time

Measuring Time in the 16th Century

"The Seven Ages of Man' Give Meaning to Each Stage of Life

How GMT is being used today?

Uses of GMT go from email time stamp to air travel


Lunar Calendars

Types of lunar calendars observed around the world ,

2016 and 2017 dates

Days of the Week

Official European Union Languages

A multi-lingual Monday to Sunday

Time Management

It cannot be stored or saved for later. Time can only be managed

We all know the theory of how to use time better, how do we put it in practice?

World Time Zone Map

Map of Global Time Zones

Solstice and Stonehenge

The magic of midsummer in a magical place

The longest day of the year is called the summer solstice in the Northern Hemisphere

Roman Numerals

Why do clocks use IIII instead of IV for 4?

Still a puzzling choice


Precise Clock

NIST scientists have built a second "quantum logic clock," using quantum information processing techniques on a single ion of aluminium to make a clock that would not gain or lose more than one second in about 3.7 billion years.  

The Winter Solstice

Time Management Part II

Plans exist to be reviewed. The joy of discarding them

Adding new decisions, taking outdated ones off the list

Leap Second

The adjustment between Atomic & Earth Time

All in One: World and Local Clocks

Digital timepieces for real and virtual travel

The World is local, so is the time

Time and Cricket

A complex relationship

Anna Monks

Railway Time

From natural time to clock time

For many centuries, there was little need for time to be accurately measured. The transition from day to night, the movement of the moon and the changing of the seasons were enough to measure large units of time, and for most people, the passing of the sun through the sky was adequate to indicate sunrise, sunset and mid-day.

GMT Timestamp

GMT Server Time Stamp:

The upper time stamp is taken from our server which is synchronized to the NTP network and should be accurate within 1 second. The lower timestamp is the time on your computer , converted to GMT. Therefore, if your computer's time is correct, there should not be more than a 2 second difference between the upper and lower time stamps. The extra second is to allow for network delay and the conversion process from your computer's time to GMT.

Frequently Asked Questions - FAQs

UTC - Universal Time Coordinated

What is Coordinated Universal Time?

Coordinated Universal Time ( UTC ) replaced Greenwich Mean Time (GMT) as the World standard for time.  UTC is based on atomic measurements rather than the earth's rotation. Greenwich Mean Time (GMT) is still the standard time zone for the Prime Meridian (Zero Longitude).

New Zealand at Autumn Equinox Time

Free Newsletter

ISO Time

What is the time in ISO format?

The International Organization for Standardization ( ISO ) is a worldwide federation of national standards bodies from some 130 countries, one from each country.

A Brief History of British Summer Time (Daylight Saving Time)

Sun at its highest in the sky is noon at Greenwich

Note: The UK clock changes abide by EU rules

The History of Time Zones

Standard Time and Longitudes

24 time zones and many more subdivisions

Name of Months

Month names inevery major European language

A linguist's calendar

Did Columbus find longitude?

Christopher Columbus

Columbus twice claimed to have found his longitude by timing lunar eclipses. These claims are probably inaccurate.

Global Time

What time is it now across the World?

By using your computer's clock, this calculates the time in other time zones all over the world! Useful if you communicate across different time zones for business or leisure.

What is the SI unit of time?

Official definition of a second

What is the definition of a second?

As the definition of time evolved, so did the second's

Earth Time and Atomic Time have to be 'reconciled'

British Summer Time (BST) Dates 1950-2015

When did summer time start/end ?

Check a particular year for BST start and end

When did the millennium begin?

This millennium (and century) officially began on: 1 January 2001 GMT

The simple explanation is that our Calendar System began at 1AD.  There was no year 0.  The calendar we use today goes from 1BC to 1AD.

What is the International Atomic Time Scale?

In tune, on time and in time

Tempo, beats and time signatures in music

What does music teach us about the perception of time?


Network Time Protocol

NTP is a protocol designed to synchronize the clocks of computers over a network. NTP version 3 is an internet draft standard, formalized in RFC 1305. NTP version 4 is a significant revision of the NTP standard, and is the current development version, but has not been formalized in an RFC. Simple NTP (SNTP) version 4 is described in RFC 2030.

The International Meridian Conference, Washington, 1884

The Prime Meridian at Greenwich becomes the point of reference

Why is Greenwich the "centre of time and space"?

Bristol Time

What is Bristol Time?

The clock with two minute hands, one is GMT


History of Sundials

GMT - Greenwich Mean Time

Global Time Zones - What time is it anywhere in the World?

A cross-check table with GMT offsets

Time Ball

What time does the time-ball drop at Greenwich?

In 1833 a red "Time Ball" was installed on the roof of the Royal Observatory Greenwich

A Chinese New Year

UK Clock Changes and the Anatomy of a Second

GMT, BST, UTC - plus EU legislation

Summer Period - The Full Story

Instant time conversion between world locations

How to view local current time differences and GMT offsets

GMT is both a timezone and the reference point for the Prime Meridian

Mardi Gras

"Fat" or Shrove Tuesday

First, determine the date for Easter of any given year (which is the first Sunday after the first full moon that follows the Spring Equinox) and then count back 47 days (40 days of Lent plus Holy Week) to find Mardi Gras Day.

BBC Pips

Greenwich Time Signal

For 75 years the major global news headlines of the day have been preceded by the six Greenwich Time 'pips'.  When the news of Neil Armstrong's first steps on the moon , President John F Kennedy's assassination and the destruction of the Berlin Wall were broadcast across the world on the BBC, they followed the familiar sound of the Greenwich pips.

It's official: we're ruled by time

Time is the most popular common noun in English

We like to be punctual, we expect our trains to run to schedule, and many of us spend our working day watching the clock. Now the new revised eleventh edition of the Concise Oxford English Dictionary can officially confirm that we are indeed ruled by time .

Why is the Navy so involved in time-keeping?

The earliest users of accurate time were the navy

Precision is not optional at sea

The International Meridian Conference

Washington DC, USA - October 1884

From pages 199 to 204:

Zulu Time

How is it defined?

Zero or Prime Meridian Time

The International Meridian Conference

Washington DC, USA - October 1884

Extract from one of the middle sessions of the Conference:

Time Websites

Royal Observatory Greenwich

From sundials to research on time

Panchang - Indian Astrology

Master your time - master your life

Panchang is a system based on Indian astrology, a spiritual and scientific calendar, with very practical aims.


Measuring Time by Days and Months

Moon Cycles, Solar Years and Seasonal Rhythms

British Summer Time

British Summer Time (BST) is the UK name for Daylight Saving Time

In 2017 BST runs from Sunday 26 March 01:00 GMT - Sunday 29 October 01:00 GMT (02:00 BST)

A.M. and P.M.

Non-abbreviated form: Ante and Post Meridiem

What is Noon and Midnight?

Military & Civilian Time Designations

From Time Zone A - Z

There are 25 integer World Time Zones from -12 through 0 (GMT) to +12. Each one is 15° of Longitude as measured East and West from the Prime Meridian of the World at Greenwich, England. Some countries have adopted non-standard time zones, usually 30 minutes offset which have a * designation.

Astrology: Natal Chart

The planets at the moment of your birth

Astrologers believe that the planets at the moment  of your birth have key influences on your personality.  In order to calculate your Natal (or birth) Chart you will need to know the Time and Place of your birth.  Most people know their Sun sign (the position in the zodiac that the Sun was in on your birth-date.  The position of all the planets is described in your Natal Chart.  You will also need an Ephemeris to help calculate this.


From Intuition to Classical Physics

Measurement of Time Provides Possible Answers

Summer Time and Time Zones

Daylight Saving Time (DST) extends beyond the astronomical summer

Civilian designations relative to GMT

Calendar Systems

The systems that sort out the year

The last millennium would have been celebrated in Greenwich, England on 25 March 1001 AD but it wasn't a thousand years ago because we "lost" 11 days along the way!

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