This ninety-foot tall pyramid was built during the eleventh to thirteenth centuries directly upon the multiple foundations of previous temples. The architecture of the pyramid encodes precise information regarding the Mayan calendar. Each face of the four-sided structure has a stairway with ninety-one steps, which together with the shared step of the platform at the top, add up to 365, the number of days in a year. These stairways also divide the nine terraces of each side of the pyramid into eighteen segments, representing the eighteen months of the Mayan calendar. The pyramid is also directionally oriented to mark the solstices and equinoxes. The axes that run through the northwest and southwest corners of the pyramid are oriented toward the rising point of the sun at the summer solstice and its setting point at the winter solstice. The northern stairway was the principal sacred path leading to the summit. At sunset on the vernal and autumnal equinoxes, an interplay between the sun's light and the edges of the stepped terraces on the pyramid creates a fascinating - and very brief - shadow display upon the sides of the northern stairway. A serrated line of seven interlocking triangles gives the impression of a long tail leading downward to the stone head of the serpent Kukulkan, at the base of the stairway. Adjacent to the head of Kukulkan, a doorway leads to an interior staircase ending at a small and very mysterious shrine.
(NB The image and text above is from the Sacred Sites web site) hide this.

By gathering data regarding the movement of celestial bodies, the Stonehenge observations were used to indicate the appropriate days in the annual ritual cycle. In this regard, it is important to mention that the structure was not used only to determine the agricultural cycle, because in this region the summer solstice occurs well after the growing season begins and the winter solstice well after the harvest is finished. Concerning its architectural form and function, scholars have suggested that Stonehenge, especially in its middle and later form, was intended to be a stone (and thereby imperishable) replica of the kind of wooden sanctuary that was more locally common in Neolithic times. What was the nature of the rituals performed at Stonehenge? Ray theorizes that, because Stonehenge is situated in an area rich in burial tombs, it may have had some relevance in burial rituals. Its shape, which resembles that of Neolithic ceremonial buildings, however, points more to its probable use as a shrine for the living rather than for the dead. As a temple for the living, Stonehenge's capacity to determine the dates of the solstices and equinoxes becomes all-important. Throughout the ancient world people have regarded the sun and moon as sacred beings whose cyclical rhythms, with their seasonal strengthening and weakening, had a positive, magical, and rewarding effect upon the life of human beings. Stonehenge and the large number of other stone rings located throughout the British Isles (and the world) are part solar/lunar/stellar observatory and part ritual structure.
(NB The image and text above is from the Sacred Sites web site) hide this.

One of the great puzzles for scientists throughout the ages was how to measure the exact size of the Earth and how to establish a system for plotting towns and cities on its surface. The ancient Greeks discovered very early on that by measuring the apparent movement of the Sun and the stars – the science of astronomy – they could roughly work out the Earth’s size and establish certain surface co-ordinates relative to its equator. These north/south co-ordinates were called latitude. It soon became clear, however, that it was much more difficult to define east/west co-ordinates because there was no fixed point from which to measure. Early civilisations set up a series of arbitrary ‘zero points’, based on important landmarks or large cities, from which they calculated longitude. But finding longitude on land could still only be done by pacing out distances. There seemed no scientific means for working out how to calculate longitude. The difficulty in calculating longitude became particularly serious from the 15th century onwards, when explorers in search of new worlds began to take to the high seas in large numbers. It was one thing not to know one’s longitude while travelling on land: but not being able to calculate it at sea meant that navigators were often sailing without knowing how far east or west they were from land. Using a method known as ‘dead-reckoning’, sailors could make an educated guess about their location by setting the speed of the ship against the angle of the prevailing winds, but cloudy nights or sudden storms at sea often led to shipwreck and tragedy.

Founding the Observatory

‘When Charles II, King of England, was informed of these facts, he said that the work must be carried out in royal fashion. He certainly did not want hos ship-owners and sailors to be deprived of any help the heavens could supply, whereby navigation could be made safer.’ (John Flamsteed, Historica Coelestis Britannica, 1725)

The discovery of the New World and new trade routes to the riches of the East led a number of small maritime nations towards a quest for wealth and empire. The heavy reliance on sea trade and the sheer volume of goods and ships held hostage to the sea meant that finding an answer to ‘the longitude problem’ became an international priority. Not only did every nation which could do so first. In 1674, King Charles II became convinced that there might be an astronomical solution to the longitude problem. His mistress, Louise de Kerualle, Duchess of Portsmouth, had met a Frenchman, a certain Sieur de St Pierre, who claimed that one could plot the motions of the Moon against the field of stars and use the heavens like a big clock in order to determine longitude. Charles II commanded four of his most trusted advisors to discover if such a scheme were, indeed, possible. They asked the noted astronomer, John Flamsteed, for his opinion. Flamsteed replied that the Sieur’s proposals were ridiculous given the current state of the astronomical knowledge required: the maps of the stars were inaccurate, there were no reliable tables of the Moon and there were certainly no charts comparing the movements of the Moon against the sphere of the fixed stars.

As a response, Charles II decided that the only way to improve matters was to found an Observatory and he immediately appointed Flamsteed as the first Astronomer Royal. His task was ‘…to apply himself with the utmost care and diligence to rectifying the tables of the motions of the heavens, and the places of the fixed stars, so as to find out the so much-desired longitude of places for the perfecting the art of navigation’.

Building Flamsteed House

‘… we have resolved to build a small observatory within our park at Greenwich, upon the highest ground …’ (Royal Warrant, 22 June 1675)

Charles II instructed Sir Jonas Moore, Surveyor-General of the Ordnance, to begin construction of his royal observatory. The foundation stone was set at 3:14 pm on 10 August 1675. As befitted the superstition of the day, Flamsteed himself plotted the horoscope for the future success of the Observatory. The inscription on his drawing tells us, however, that neither Flamsteed nor his colleagues were believers in the occult sciences. It says: ‘Can you keep from laughing my friends?’ The main part of the early Observatory was designed by Sir Christopher Wren, who had himself been a professor of astronomy. The original Observatory had three main floors: a basement area containing a small kitchen, with a small wash-house and workroom nearby; the ground floor with four main rooms of reception hall, study, bedroom and dining room; and the crowning glory of the building, the octagonal ‘Star Room’. As Wren recalls in one of his later letters, the building was designed ‘for the Observator’s habitation … and a little for Pompe’. Among the stipulations, Charles II insisted that the whole building should not cost the Crown more than £500. The work itself was financed through the sale of some old, decayed gunpowder. Most of the bricks came from Tilbury Fort and some of the wood, iron and lead was taken from a recently demolished gatehouse in the Tower of London. The exterior was completed by Christmas 1675 and Flamsteed together with two servants, moved in on 10 July 1676. the total cost to the Crown had been £520 9s 1d.

The Octagon Room

The tall windows of the Great Star Room - or the Octagon room, as it is called today – were designed to accommodate the long telescopes used in the 17th century. All these telescopes worked by refracting, or bending, light. Another key instrument used by astronomers was the quadrant. The arc of degrees was engraved on a quarter of a circle of brass and the addition of sights or a telescope enabled astronomers to measure the altitude, or height, of celestial bodies. The great panorama of the sky offered by Wren’s design for the Octagon Room meant that the Observatory was perfectly laid out for observing celestial events such as eclipses, comets, and planetary movements. Perhaps the major feature of the Octagon Room is the pair of year-going clocks built for Flamsteed by Thomas Tompion in 1676. Before Flamsteed could begin his great task of charting the stars, he needed to establish that the Earth rotated at an even rate, so he would have a constant figure as the basis of his measurement. The newly invented pendulum clock provided the first reliable tool with which the rotation of the Earth could be verified. To meet the necessary standards of precision, Tompion devised a very long 13-foot pendulum for each clock. It was thought that since a longer pendulum meant a smaller swing of arc, it would provide more reliable time measurements. The clocks beat once every two seconds and needed winding only once a year. By the summer of 1676, Flamsteed had proved, to the limit of the technology available to him, that the Earth did indeed rotate at an even rate. From his observations, he developed the formula for the ‘Equation of Time’, which records the changing relationship between mean time and Earth-Sun time. It was not until the invention of the quartz-crystal mechanism in the 1930s that the true irregularity in the speed of the Earth’s rotation was discovered.

The First Greenwich Meridian

It were much to be wanted our walls might have been meridional but, for saving of Charges, it was thought fit to build upon the old ones which are some 13½° false and wide of the true meridian …’ (John Flamsteed, 1676)

Flamsteed’s job was to draw up a map of the heavens, sufficiently accurate to be reliable for astronomical navigation. The way to map the stars (the basis of positional astronomy) is to set up a sighting instrument or telescope along a meridian, or north-south line. As the stars appear to rotate above the astronomer’s head, he can measure the position of each star against his meridian, it is possible to build up an accurate map of the night sky. Unfortunately, because Wren’s Observatory had been built on the foundations of an earlier tower, it did not run true to the meridian but headed off slightly to the west. For the purpose of mapping the heavens, Wren’s Octagon Room was useless. Instead, Flamsteed set up his positional observatory in a small shed at the bottom of his garden. For the next 43 years, Flamsteed’s worked in his observatory, exposed to the night air with the roof shutters drawn back, measuring the transits of the stars over his head. This small building, housing Flamsteed’s 7-foot astronomical sextant and his 7-foot mural arc, became the real basis of the rest of the Observatory. When Edmond Halley was appointed Astronomer Royal in 1720, he noticed that Flamsteed’s brick meridian wall was beginning to subside down the hill into the Riyal Park. Halley proposed to build a new meridian wall, but positioned slightly to the east, upon which he hoped to place two new astronomical quadrants. This move established the pattern for the later growth and expansion of the Observatory. Each time a new or better positional telescope was needed, a new room would be added to the exciting structure: always in line with the original meridian but successively further east each time. Walking eastward from Flamsteed’s original meridian, one encounters three later meridian lines: those of Halley, Bradley and Airy – the last of which was recognised in 1884 as the Prime Meridian of the world.

Bradley’s Meridian and the Ordnance Survey

James Bradley, the 3rd Astronomer Royal, was known as one of history’s most accurate observers. His skill led to two very important astronomical discoveries. He was the first astronomer to explain that the position of some stars appears to change throughout the year because the Earth itself was moving around the Sun. This celebrated discovery of the ‘Aberration of Light’ and the ‘Constant of Aberration’ provided a new level of accuracy for all celestial observations. Bradley also noticed that the star, Gamma Draconis, which was often studied by the astronomers at Greenwich because it passed directly above the zenith of the Observatory, appeared to change its position in the sky – as much as 1 second of arc in three days and far too much to be due to the aberration of light. After much work, Bradley realised that the apparent change in Gamma Draconis was actually the result of the Earth wobbling on its own axis due to the gravitational pull of the Moon and that this movement, known as ‘nutation’, went through a full cycle every 19 years. In 1749, Bradley received money from the Board of Ordnance to build a ‘new Observatory’ adjacent to Halley’s Quadrant Room. Here he set up his principal telescope, an 8-foot transit instrument by the celebrated instrument maker, John Bird. When the French and the English embarked on their great joint project to measure the distance between Paris and Greenwich Observatories, the cartographers used the meridian defined by Bradley’s new telescope as the official Greenwich Meridian. Bradley’s Meridian was also used as Longitude 0° in the first Ordnance Survey map, one of the County of Kent first published on 1 January 1801. It remained the official Prime Meridian of Britain until 1850, when the 7th Astronomer Royal, Sir George Biddell Airy, decided to build a new transit circle in the room adjoining Bradley’s instrument. To this day, however, all maps produced by the Ordnance Survey still use Bradley’s Meridian as their Longitude 0°.

‘…A Publick Reward…’ (The Longitude Act, 1714)

Regardless of the progress being made at Greenwich to find a solution to the longitude problem, a series of maritime disasters prompted the British government to seek out alternative means to quicken its discovery. The most notable tragedy occurred on 22 October 1707, when four Royal Navy ships led by Admiral Sir Clowdisley Shovell struck the treacherous ledges off the Isles of Scilly. They foundered resulting in a loss of nearly 2,000 lives. Parliament responded to the public outcry by appointing a panel of experts, the Board of Longitude and, in 1714, offering a prize of £20,000 to anyone who could discover a way to determine longitude at sea to within half a degree and £10,000 for to within one degree. As well as attracting serious scientific interest, the Longitude Prize acted as a magnet for any number of crack-pots and their bizarre proposals. Barges moored around the world, all firing flares at midnight, and perpetual motion machines sealed in giant vacuum bottles seem sane in relation to some ideas. One person, for example, claimed to have discovered a mysterious ‘Powder of Sympathy’. When the powder was sprinkled on a knife which had inflicted a wound on someone, the action would cause that person to re-experience the original pain. The suggestion was made that if a number of dogs were all wounded with the same knife, they could be placed on the different ships in His Majesty’s fleet. Everyday at noon, someone at Greenwich could plunge the knife into the Powder of Sympathy and all the dogs would yelp at the same time, regardless of where they were. By knowing that it was noon in Greenwich, navigators had once essential ingredient towards being able to calculate their longitude at sea. Needless to say, the Board of Longitude were not impressed! Scientists had long realised that the ideal solution to the Longitude Problem was some mechanism which would allow you to know how far you were from a zero point (such as Greenwich) in terms of time, because longitude is a coefficient of time. Since the 360° circumference of the Earth completes one full rotation every 24 hours, each hour’s worth of time equals 15° worth of rotation, or 15° difference in longitude. In the mid-18th century, there simply was no mechanism that was able to keep good time on a sea voyage, given the heaving motions of a ship and the potential for extremes of heat and cold as the vessel travelled from the Arctic to the Tropics on voyages of exploration, ot in search of trade. Even the great Sir Isaac Newton declared: ‘… such a watch hath not yet been made.’

John Harrison: The Man who Found Longitude

John Harrison was born in 1693, the son of a village carpenter. By the age of 20, he had taught himself the theory and practical skills of clockmaking and, when the longitude prize was announced, Harrison was sure that one of his clocks would win it. In 1730, following four years of careful thought and study, he had formulated a plan for his first sea-going clock. Taking his plans with him, he set off from his home in Lincolnshire for Greenwich to seek advice from Edmond Halley, who was Astronomer Royal at the time. Halley received Harrison kindly and provided an introduction to the greatest clockmaker of the day, George Graham. Graham was entranced by Harrison’s plans and even offered him a loan to complete the clock! Harrison spent the next six years constructing the timekeeper, now known as H1’. He then brought it to Graham in London, who arranged to have the timekeeper publicly displayed to the scientific community. It instantly became quite a celebrity, with several contemporary chroniclers claiming it to be one of the great marvels of the modern age. On its first sea trials, H1 performed admirably. The Board of Longitude was suitably impressed but Harrison felt he could better H1’s performance and convinced the board to advance him £250 to begin work on H2. Harrison immediately set to work on H2 but soon realised that the machine contained certain deficiencies in its design. He began a third version, H3, and for 19 years Harrison obsessively built and rebuilt this, supported by grants from the Board of Longitude, who (it must be admitted) were beginning to lose both patience and confidence that Harrison would ever produce the much-vaunted successful marine timekeeper. The great breakthrough came in 1753, when Harrison commissioned a watchmaker to make a small pocket-watch to his design, which he could use to test the accuracy of his large timekeepers. As soon as he tested the watch he realised that he had spent the past 27 years barking up the wrong tree. A small timepiece, with a high-frequency oscillator, could be fashioned into a much more stable timekeeper than a huge portable sea-clock would ever be.

The Great Competition

‘But they still say a watch … can be but a watch … and that the performance of mine (though nearly to truth itself) must be altogether a deception.’ (John Harrison, 1763)

In 1755, Harrison approached the Board asking for funds to help him develop H4. Not only were they unsympathetic but their attention had been turned away from marine timekeepers towards a different method that seemed substantially closer to fruition. The invention of the reflecting quadrant by John Halley in 1731 had made the business of measuring celestial angles much more precise. The publication of new lunar tables, recently compiled by Professor Tobbias Mayer of Gottingen, meant that the old proposal of an astronomical solution to the longitude problem was revived. At the same time Harrison was asking for money to complete H4, the new Astronomer Royal, Nevil Maskelyne recommended to the Board that it was now the moment to reconsider the potential of the lunar distance method for finding longitude at sea. In 1766, Maskelyne had published the first edition of The Nautical Almanac, which supplied all the observational data necessary to take a lunar-distance at sea. It gave the exact angle between the Moon and certain fixed stars, measured from the Observatory at three-hourly intervals throughout the year. Using these tables, the able navigator could begin to calculate the time at Greenwich from the position of the stars above his head. Once he knew that time at Greenwich, he was half-way towards finding his own longitude at sea. H4 had failed its first sea-trial and, in August 1763, Maskelyne was sent to Barbados in order to set up an observatory to check the watch’s performance when it arrived on its second trial. As it turned out, H4’s performance was three times better than the performance rates stipulated by the original Longitude Act. The Board, however, had now fully turned against Harrison. It refused to award him the Prize, stipulating that he would first have to divulge the watch’s secrets, allow another watchmaker to copy his design and provide two additional copies of the watch himself before the Board would even consider another request for money. Furthermore, they instructed Maskelyne to collect all four timekeepers from Harrison’s home, lest Harrison consider selling their secrets abroad. Copies of H4 were duly made, the watch itself underwent a 10-month trial at the Observatory and still the Board refused to award the Prize. Finally, in desperation, Harrison decided to approach King George III directly and request an opportunity to have one of the copies tested by the King himself at his private observatory at Kew. H5 went on trial from May to July of 1772, its daily rate over a 10-week period averaged out at less than a third of a second a day. Harrison approached the Board again, only to be told that ‘no regard will be shewn to the result of any trial made of them in any other way’. Finally, it was only on the recommendations of a specially appointed parliamentary financial committee that Harrison was awarded the final £8,750 due to him through the special condition of a Royal Assent. So, technically, he never won the Longitude Prize, though the world now recognizes him as the man who had, indeed, ‘found longitude’.

The Creation of Standard Time

Up until the mid-19th century, every individual town around the world kept local time. There were no national or international conventions as to how time should be measured or when day would begin and end. Some countries, for example, used the system of ‘unequal hours’, which meant that the length of the hours would vary during the year as the balance between day-time and night-time hours changed with the passing of the seasons. For most, it meant that each town or city had a day made of 24 ‘equal hours’, with the primary fixed point of day being noon; that is, the moment when the Sun reached its zenith and crossed the local meridian. This moment was easily measured with a sundial, against which people would set their watches. Since the Sun passes over any number of meridians in succession as it appears to travel from east to west, the occurrence of ‘local noon’ also moves from east to west. When it is noon in London, it is already 12:05 p.m. in Norwich but only 11:44 a.m. in Plymouth owing to their relative distances east and west of the Greenwich Meridian. Putting it another way, the Sun appears to move 1° of arc across the sky every four minutes, of 15° every hour: Norwich is 1° 15’ east of Greenwich and Plymouth is 4° west of it. Such changes in local time did not really matter until the development of the railway networks. With each town on the railway line following its own local time, the organisation of railway timetables became a nightmare. There was one period, in the United States, when each of the 80 different railway systems kept their own timetables based on the local time of the home depot. A traveller journeying from Maine to California would have had to change his watch at least 20 times during the trip in order to be sure of not missing a connection! These sorts of problems were magnified with the development of the electric telegraph. The first successful marine cable was laid across the English Channel in 1851 and, by 1860, London was connected to the Indian sub-continent by a cable running between Malta and Alexandria. Under the direction of the American, Cyrus W. Field, 1,879 nautical miles of cable connected Ireland to Newfoundland in 1865-66. For the first time in history, virtually every major city could be in direct and immediate contact with the rest of the world. But there was still no internationally agreed system of timekeeping.

Greenwich Time for Britain

The Royal Observatory has long been the home of precision timekeeping in Britain. The astronomer’s reliance on ‘state-of-the-art’ timekeeping for the purpose of positional astronomy meant that the best clocks –regulators and marine chronometers – all found their way to Greenwich for testing and approval by the Astronomer Royal. The Observatory had set a large Time Ball on the roof of Flamsteed House in 1833 to serve as a visual time signal for all the navigators in the River Thames, who would use the Ball’s daily drop at 1:00pm to calibrate their marine chronometers. Later, in 1836, the Observatory began to provide the service of ‘distributing time’ to all the principal chronometer makers in London. John Henry Belville and later his daughter, Miss Ruth Belville, were charged with rating a large pocket chronometer by John Arnold against Greenwich Mean Time each Monday morning, before setting out down Greenwich Hill into the City of London. As one contemporary records: ‘… she always referred to the watch as Arnold, as if it were the Christian name of a dear friend. Her business with a client would be performed something like this: “Good morning, Miss Belville, how’s Arnold today?” – “Good morning! Arnold’s four seconds fast today” and she would take Arnold from her handbag and give it too you… The [client’s] regulator or standard clock would be checked and the watch handed back; and that would be the transaction for the week’. The astronomers themselves always used sidereal time (time measured by the stars) but, for civil purposes, they set up a new timekeeping system now known as Greenwich Mean Time (GMT). Because the Earth rotates on a tilted axis and the speed of its orbit changes, the Sun appears to move across the sky at slightly different rates throughout the year. The time measured by a sundial can be up to 16 minutes faster or slower than the time measured by a clock. The Mean Solar Day or an average solar day based on taking the average of a year’s worth of days was established to provide a more uniform unit of time. Greenwich Mean Time is based on the Mean Solar Time as it is measured from the Greenwich Meridian. Realising Greenwich’s responsibility in the distribution of time, the 7th Astronomer Royal, Sir George Biddell Airy, set up a great electrical ‘master’ clock at the Observatory which provided impulses to a number of ‘slave clocks’ throughout the nation. The master was designed by the London clockmaker, Charles Shepherd, and was installed in 1852. By the mid-1950s, the necessity for a standard time in Britain became the subject of heated debate. Many people, particularly those in the north and west of the country, resented the imposition of a standard time measured at Greenwich. Some called it ‘railway aggression’, thinking that this new proposal was just some clever ploy by the government and big business, aimed against the common man. By 1855, however, 98% of all the public clocks in Britain were set to GMT. None the less, it was not until 2 August 1880 that GMT was given Royal Assent as British Standard Time.

Greenwich Time for the World

The need for a standard time in Britain, where the maximum difference in longitude equals less than 30 minutes of time, was mild compared to the problems facing Canada and the United States, where the difference between east and west coasts added up to more than 3 ½ hours. Professor Charles Ferdinand Dowd was the first to propose that both countries adopt an international time-zone system, whereby every 15° of longitude would equal one hour’s worth of time and the time would be uniform across each 15° zone. Dowd’s proposal was accepted as law in the United States in 1883, with the peculiar wrinkle that Greenwich (rather than an American town) was chosen to serve as Longitude 0° for the whole system. At the same time, discussions were taking place in various world capitals about the possibility of establishing a time-zone system for the whole world. As one might expect, the main sticking point was which nation would be accorded the honour of being the home of the ‘Prime Meridian of the World’. In October 1884, 41 delegates from 25 nations convened in Washington DC for the International Meridian Conference. By the end of the conference seven important principals had been voted through:

1. it was desirable to adopt a single world prime meridian, in place of the innumerable meridians that existed.
2. that the meridian passing through the principal transit instrument at the Observatory at Greenwich was to be this ‘Initial Meridian’.
3. that all longitude would be calculated both east and west from this meridian up to 180°
4. that all countries would adopt a universal day.
5. that the universal day would be a Mean Solar Day, beginning at the moment of Mean Midnight at Greenwich and counted on a 24-hour clock.
6. that nautical and astronomical days everywhere would begin at Mean Midnight and
7. that all technical studies designed to regulate and extend the application of the decimal system to the division of time and space would be supported.

Greenwich had won the prize of Longitude 0° by a vote of 22 in favour to one against (San Domingo), with two abstentions (France and Brazil). There were two main reasons for the victory. The first was the fact that the United States had chosen Greenwich as the basis for its own national time-zone system. The second, pointed out by the British delegate representing Canada, Sandford Fleming, was that if one calculated the total tonnage of vessels sailing the seas, 72% of the world’s commerce depended on sea-charts which used Greenwich as the Prime Meridian. The decision, essentially, was based on the argument that naming Greenwich as Longitude 0° would inconvenience the least number of people! hide this.