Many believe that our civilization is a source of constant progress, and all the most interesting discoveries and developments are yet to come. However, deep philosophical works, some architectural masterpieces and even devices created long before us clearly highlight the incompleteness of this concept. The ancient scientists also knew a lot, they created buildings and things, the principle of work and the purpose of which are not completely understood. The clear consistency of the functioning of various devices with the laws of physics and the incontrovertibility of the information obtained with their help are often shrouded in legends. Such instruments include astrolabe, an ancient astronomical instrument.
Appointment
As the name implies (“aster” in Greek means “star”), the device is associated with the study of celestial bodies. Indeed, astrolabe is a tool that allows you to calculate at what height relative to the surface of our planet there are stars and the Sun, and based on the data obtained to determine the location of an earthly object. On long trips by land and by sea, the astrolabe helped determine the coordinates and time, and sometimes served as the only guideline.
Structure
An astronomical instrument consists of a disk, which is a stereographic projection of the starry sky, and a circle with a high rim, in which the disk is embedded. The base of the device (an element with a side) has a small hole in the central part, as well as a suspension ring, necessary to facilitate the orientation of the entire structure relative to the horizon. The middle part is composed of several circles with lines and points plotted on them that define latitude and longitude. These discs are called tympans. The goniometric astronomical instrument possessed three such elements, each of them suitable for a certain latitude. The order in which tympans were inserted depended on the terrain: the upper disk had to contain the projection of the sky corresponding to a given section of the Earth.
On top of the tympans was a special lattice (“spider”), equipped with a large number of arrows indicating the brightest stars indicated on the projection. Through the holes in the center of the tympanum, the grill and the base passed the axis, holding the parts together. Alidada was attached to it - a special ruler for calculations.
The accuracy of astrolabe is astonishing: some devices, for example, are able to show not only the movement of the Sun, but also deviations that periodically occur in it. Interestingly, an ancient astronomical instrument was being created at a time when the geocentric picture of the world ruled. However, the idea that all celestial bodies revolve around the Earth did not prevent the ancient scientists from creating such an accurate device.
A bit of history
The astronomical instrument has a Greek name, but many of its components bear the names of Arab origin. The reason for this seeming discrepancy in the long journey that the device overcame during its formation.
The history of the development of astronomy, like many other sciences, is inextricably linked with Ancient Greece. Here, about two centuries before the beginning of our era, a prototype of astrolabe appeared. Hipparchus became its creator. Already in the second century after Christ, a description of a goniometer similar to the astrolabe was made by Claudius Ptolemy. He built a tool that can determine the location of stars in the sky.
These first devices were somewhat different from the astrolabes, which modern man imagines them and which are exhibited in many museums around the world. The invention of Theon of Alexandria (IV century AD) is considered to be the first instrument of the familiar structure.
Eastern sages
The history of the development of astronomy in the early Middle Ages began to unfold on the territory of Islamic states. This was due to the persecution of scientists by the church, with the attribution to instruments like astrolabe of satanic origin.
Arabs improved the instrument, began to use it not only to determine the location of stars and orientation on the ground, but also as a time meter, an instrument for some mathematical calculations, a source of astrological predictions. The wisdom of the East and West merged into one, the result was an astrolabe device that combined European heritage with Arabian thought.
Pope and devil tool
One of the Europeans who sought to revive the astrolabe was Herbert of Orilliac (Sylvester II), who briefly held the post of Pope. He studied the achievements of Arab scholars, learned to use many tools forgotten from antiquity or banned by the church. His talents were recognized, but his connection with alien Islamic knowledge contributed to the emergence of a number of legends around him. Herbert was suspected of being associated with a succubus and even the devil. The first gave him knowledge, and the second helped to occupy such a high position in the church hierarchy. Unclean attributed to his ascent. Despite all the rumors, Herbert was able to revive a number of important devices, including astrolabe.
Return
After some time, in the XII century, Europe began to use this device again. At first, only the Arab astrolabe was in use. It was for many a new tool, and only for some - the forgotten and modernized heritage of their ancestors. Gradually, analogues of local production began to appear, as well as long scholarly works related to the use and installation of astrolabe.
The peak of popularity of the device came in the era of the Great Discoveries. In the course was a sea astrolabe, which helped to determine where the ship was. True, it had a feature that negated the accuracy of the data. Columbus, like many of his contemporaries traveling on water, complained that this device cannot be used in pitching conditions, it is effective only when there is still calm land or sea under your feet.
The device was still of some value to mariners. Otherwise, one of the ships on which the expedition of the famous explorer Jean-Francois Laperouse would have gone on a trip would not have been named. The ship "Astrolabe" is one of two that participated in the expedition and mysteriously disappeared at the end of the eighteenth century.
Decoration
With the advent of the Renaissance, “amnesty” received not only various devices for exploring the world, but also decoration, a passion for collecting. Astrolabe is a device, among other things, often used to predict fortunes by the movements of stars, and therefore it was decorated with various symbols and signs. Europeans took over the Arabs' habit of creating instruments that were accurate in terms of measurements and externally elegant. Astrolabes began to appear in the collections of courtiers. Knowledge of astronomy was considered the basis of education, the possession of the device emphasized the scholarship and taste of the owner.
Crown Collection
The most beautiful instruments were encrusted with precious stones. Pointers were given the shape of leaves and curls. Gold and silver were used to decorate the instrument.
Some masters devoted almost entirely to the art of creating astrolabes. In the XVI century, the most famous of them was considered the Flemish Gualterus Arsenius. For collectors, his products were the standard of beauty and grace. In 1568 he was ordered another astrolabe. The instrument for measuring the position of stars was intended for the Austrian army Colonel Albrecht von Wallenstein. Today, this copy is stored in the museum. M.V. Lomonosov.
Shrouded in mystery
Astrolabe, one way or another, slips in many legends and mystical events of the past. So, the Arab phase of its history gave the world the myth of the treacherous Sultan and the scientific abilities of the court astrologer Biruni. The ruler, for a reason hidden for centuries, took up arms against his predictor, decided to get rid of him with the help of cunning. The astrologer had to specify exactly which exit his master would use, or suffer a fair punishment. In his calculations, Biruni used astrolabe and, writing the result on a piece of paper, hid it under the carpet. The cunning sultan ordered the servants to cut a passage in the wall and left through it. When he returned, he opened a paper with a prediction and read a message there, foreseeing all his actions. Biruni was acquitted and released.
Relentless Movement of Progress
Today, astrolabe is part of past astronomy. Orientation on the ground with its help has ceased to be expedient since the beginning of the 18th century, when the sextant appeared. Periodically, the device was still used, but even after a century or a little more, the astrolabe finally migrated to the shelves of collectors and lovers of antiquities.
Modernity
A rough understanding of the device and the functioning of the device is provided by its modern descendant, the planisphere.
This is a map on which stars and planets are plotted. Its components, stationary and moving parts, in many ways resemble the base and the disk. To determine the correct position of the bodies in a particular part of the sky, an upper moving element is required, corresponding in parameters to the desired latitude. Astrolabe is oriented in a similar way. With your own hands, you can even make a semblance of a planisphere. Such a model will give an idea of the capabilities of its ancient predecessor.
Living legend
Ready-made astrolabe can be bought at souvenir shops, sometimes it appears in collections of decorative products that take the basis of sim-punk style. Unfortunately, working devices are difficult to find. Planispheres are also rare on the shelves of our stores. Interesting specimens can be found on foreign sites, but such a moving map will cost as the same cast-iron bridge. Self-constructing a model may be a matter that requires a lot of time, but the result is worth it and the children will definitely like it.
The starry sky, which so comprehensively occupied the minds of the ancients, amazes modern man with its beauty and mystery. Devices such as astrolabe make it a little closer to us, a little clearer. The museum or souvenir version of the device also makes it possible to feel the wisdom of our ancestors, who created tools two thousand years ago that allow us to accurately reflect the world and find our place in it.
Today, astrolabe is a stylish souvenir, interesting for its history and eye-catching with its unusual design. Once this was a significant breakthrough in astronomy, allowing you to correlate the position of celestial bodies with the terrain, almost the only chance to understand where the traveler was lost in the open spaces of the ocean or desert. And although the device significantly loses in functional terms to its modern counterparts, it will always be an important part of history, an object shrouded in a romantic veil of secrecy, and therefore is unlikely to be lost for centuries.