PIS bro Prazsky Orloj A5 obalka UK v2.indd 1 27.5.20 13:07 SIGNIFICANCE OF as with some exaggeration it can be said that the astronomical clock is located in the very THE ASTRONOMICAL CLOCK centre of Europe. The Old Town Astronomical Clock is a com- The Prague Astronomical Clock is a unique plicated and multilayered work. The richly medieval monument. It was built during sculptured ornamentation and painted picto- the last breaths of the cultural boom in the rial calendar plate enhance the central motif Bohemian lands that began under the reign of of the astronomical clock which is its top dial Charles IV, Bohemian king and Holy Roman – astrolabe. The astrolabe of the medieval Emperor, who transformed Prague into a clock is a rotating image of the heavens – the European centre of learning, culture and heavens showing the movement of the Sun, power. The Old Town Astronomical Clock Moon and stars, as well as the heavens that was built as one of the last medieval archaic are the seat of the God. To the medieval man, astronomical clocks. These served a different the astronomical clock seemed like a true purpose and were of a different character miracle. He admired the fact that its creator than the modern astronomical clocks that had managed not only to understand the emerged in Europe with the onset of the Re- movement of the Sun and Moon across the naissance. Its main dials – astrolabes – were sky, but also to imitate it. Everyone could read not designed to work like accurate astronomi- the details from its astrolabe – the actual cal instruments, but were to be used above all time, day in the year or how favourable the for astrological purposes. Their design is also constellation of the heavens with the stars, fundamentally opposite to the construction of Sun and Moon is in the life of the individual. astronomical astrolabes. The astronomical clock also indicates the Unlike most astronomical clocks of the time, astrological signs. Astrology and the faith which were made particularly for the interior that earthly things were ruled by the heavens of churches, the Prague Astronomical Clock were very important and commonplace for was built in between the buttresses of the life at the time. It was not only used to predict Old Town Hall tower with great sensitivity. It the future or determine the right moments faced the outer area of the square in order to for making binding decisions, but also for become a part of life in the centre of Prague. correctly timing the performance of medical Prague is often called the “heart of Europe”, treatment. WHAT THE ASTROLABE in late spring and early summer, it orbits the astrolabe in the same big arch from left to SHOWS right along its circumference. The opposite is the case in winter – the path of the Sun in the The movement sky and on the astrolabe plate is very low. of the celestial bodies The starry sky is depicted only in part – it shows the constellations of the zodiac The plate of the astrolabe represents a view through which the Sun and Moon gradually of the southern sky. The bottom is marked move throughout the year. The Sun travels by a golden line of the arch of the horizon across the entire circumference of the zodiac and above it is the blue sky showing the just as it does across the sky in one year, the movement of the Sun, Moon and stars from Moon in just under 27.5 days. The Sun and left to right, just as in nature. The stars are Moon also move very slowly along the zodia- represented as constellations marked out in cal ring anti-clockwise, then together with the an excentric circle. Sun and Moon, the zodiac rotates along the Just as the Sun moves high on the horizon astrolabe every day by one clockwise rotation. ASTRONOMICAL CLOCK 1 PIS bro Prazsky Orloj A5 UK v3.indd 1 27.5.20 16:21 PIS bro Prazsky Orloj A5 obalka UK v2.indd 2 27.5.20 13:07 At the bottom of the astrolabe below the the eleventh evening hour and then they have line of the horizon is the terrestrial surface their well-earned rest until nine o’clock in the around us. The red colour below the horizon morning. depicts the red sky (aurora) – the colour of Besides the Old Czech Time counted from the sky before the rising of the Sun and after sunset, the symbol of the Sun also shows the its setting. This colour then passes in the dark already mentioned time counted from sunrise night and is depicted by a black ring. to the moment of sunset. There are twelve Four different times such hours. They are marked in black Arabic numerals from 1 to 12 and divide the light The clock’s astrolabe dial has always illustrat- day into twelve equal parts. These are called ed not just the movements of the Sun, Moon the planetary hours, or temporal, Babylonian and stars across the sky, but also time. During or Jewish hours, but also not the same or the day, i.e. from sunrise to sunset, the golden unequal hours; unequal because the light day symbol of the Sun together with the golden is different in length in winter and different hand, indicates the time by unequal, so-called in length in summer. In winter, at around the planetary hours while moving across the time of the solstice, the Sun rises at about astrolabe. Then, throughout the day and night, today’s eight o’clock in the morning of Central the golden hand also indicates Old Czech European Time and sets at four o’clock in Time counted from the moment that the Sun the afternoon. The light day is therefore only sets. It is marked on the rotating ring on the eight hours long and one twelfth from sunrise circumference of the astrolabe by the golden to sunset, therefore one planetary hour has a Gothic numerals 1-24. This special time, mere forty minutes in the winter. In summer which has twenty-four equally long hours, one such unequal or planetary hour lasts was introduced to Czech lands from Italy by twice as long, i.e. eighty minutes. In other emperor Charles IV half a century before the words, the Sun already rises at four o’clock in astronomical clock was built. This natural the morning and does not set till eight o’clock division of the day, originally called Italian in the evening. time, later in Czech lands also Old Czech The planetary hours were also used for the Time, was first indicated by the clock not just purpose of astrology. Each planetary hour by the Sun raffia, but also by striking out the was dedicated to a different ruling planet, but number of these hours every hour on a cim- this dedication changed regularly every day in balom. It sent out the message of the actual the week and a table was written up above the time into the Old Town streets in this manner. doorways of the apostles to correctly deter- The Old Czech Time is indicated by the clock mine the currently ruling planets. Depending to this day. Up until the clock’s fire in May on the position of the Sun on the clock, it was 1945, the clock also chimed out the number possible to make astrological predictions of of hours of Old Czech Time. Based on this, earthly events or determine the best time for it also triggered the walking of the apostles receiving medical treatment, perhaps even every Old Czech hour until sunset. Today, the for the very popular and widely practised walking of the apostles passes through the bloodletting. Astrology was part of life, and open doorway at the current hour, civic time, although it principally contradicted Christian Central European Time and, according to this theology, it was more or less tolerated by the time, the chiming machine also strikes the Church. Sometimes it was even recognised number of hours. Given that it then strikes and practised by some Catholic dignitaries. DETAILS OF THE CLOCK’S STONE SCULPTURED ORNAMENTATION using the original chiming machine of the Since the mid-16th century, the clock has been The face of the mechanical part of the clock is also enhanced by intricately worked stone ornamentation. It parti- Old Czech Time, the Old Town Astronomical showing currently used hours – these are the cularly dates from the Late Gothic changes to the monument and depicts a number of contemporary and typical Clock is the only outdoor clock in Prague that 12 hours counted from midnight and 12 hours building motifs – fabulous masks, remarkable figures or mythical and real members of the animal kingdom (the strikes midnight twenty-four times instead of monkey, cat, dog, frog, owl and other animals). commencing at midday. They are marked with twelve times. But the apostles do not leave golden Roman numerals along the circumfer- the doorways, their final walk takes place at 2 ASTRONOMICAL CLOCK ASTRONOMICAL CLOCK 3 PIS bro Prazsky Orloj A5 UK v3.indd 2-3 27.5.20 16:22 A ence of the astrolabe. These hours have been on the right side of the astrolabe, just as the called “German” or “semi-astronomical” since golden hand shows the “semi-astronomical” being introduced to the clock. time, but the value of twelve, i.e. the number 1 of all hours of the first half of the sidereal day, In 1865, the sidereal time indicator was added 2 must always be added to the next numerals to the clock.