Astrolabe. Secrets and history of an ancient invention. Astrolabe Astrolabe theodolite

Despite the huge number of regularly updated inventions, nanotechnologies and other modern technology, retro is still in fashion. This style can include various fixtures, devices, furniture, clothing and even cars. Antiques are highly valued and are perceived by many admirers of this style as something incredible and miraculous. A similar aura of mystery surrounds such unusual instrument like an astrolabe. This is real ancient computer, which not many people know about.

Briefly about the item and its purpose

An astrolabe is a device for measuring horizontal angles, establishing latitude and longitude celestial bodies. It is the oldest astronomical instrument ever invented in human history. This device is based on the principle of stereographic projection. The modern prototype of the astrolabe is the planisphere. It is a moving map of the starry sky. It is usually used for student learning purposes.

History of the item's origin

The very first astrolabe device was discovered in Ancient Greece. Vitruvius first spoke about it. In his writing “Ten Books on Architecture,” he admiringly described a certain instrument, which the author called a “spider.”

According to the author, the instrument was very unusual in appearance and caused certain fears among others. Many of the people who have ever encountered this device have spoken of it as a divine artifact. Among the first authors to write treatises on this device were theologians and philosophers John Philoponus, Synesius and Severus Sebokht.

Who invented the device?

If everything is more or less clear about who invented the astrolabe, then the design of the device raised a number of questions. So, what did the table, an unusual object for that time, look like?

This device was round in shape and consisted of various grooves, small parts and gears. In the center of the object was a large drum and a circle. It was on it that the entire zodiac circle was depicted. According to an alternative version of Claudius Ptolemy, the device resembled an armillary sphere.

And only after a long time the model was refined by the Greek mathematician Theon of Alexandria. This was in the 4th century AD. True, at that time the device received a different name - “small astrolabon”.

Device improvement

Later, the astrolabe device was refined and improved. Scientists and mathematicians of the Islamic East worked on it. Thanks to their innovations, with the help of this item it was possible to determine the time of day, the duration of the night and day, and perform simple calculations to make an astrological forecast. More and more stories and writings began to appear about this device. For example, Nasir ad-Dina al-Tusi, al-Khorezmi, al-Sijizi and other eastern authors wrote about him.

Travel to Europe

Over time, the popularity of the astrolabe compass is only growing. It reaches the shores of Western Europe. On that moment in great demand enjoyed various instruments Arabic origin. Europeans also liked the astrolabe.

At one time, European craftsmen created similar devices, relying solely on the drawings of their Arab colleagues. A little later, they began to create their own models of the device, still using the drawings of oriental masters. Confirmation of this information is described in the treatises of Geoffrey Chaucer and the scientific works of Nikifor Grigoroi.

Popularity and design changes

The device's popularity peaked during the Renaissance. It was used during the astronomy education of students. At that time, gaining knowledge in the field of astronomy was a very prestigious matter. Moreover, every student was required to know how to use the treasured astrolabe.

At that time, European craftsmen paid a lot of attention to the artistic design of the device. Therefore, this item has become synonymous with talisman and antiques. Many wealthy people tried to purchase the device and add it to their collection of astrolabes. It was a matter of honor, spoke of excellent taste and indicated a high position in society.

And again modernization

Around the sixteenth century the device was again modified. According to European authors, the device long time was not finalized and was completely unadapted to European latitudes. It was more like a souvenir or a nice trinket, but not a compass or a valuable measuring instrument.

At that time, various scientists and other specialists were working on the astrolabe. Among them was the famous Flemish master Gualterus Arsenius. The products that he created literally amazed the imagination with their elegance of form and extraordinary accuracy of data. The master had no end to clients. Among them was the famous Austrian commander-in-chief Albrecht von Wallenstein. Currently, one of his collectible astrolabes is kept in the building of the M.V. Lomonosov Museum.

What parts does it consist of?

The main detail of the astrolabe is a rounded element with hanging rings to define the horizon lines and one high side. In common parlance it is called a “plate”. Inside such a circle there is a scale digitized in hours and degrees. Such markings are present along the entire perimeter of the “plate”.

Another flat disk of smaller diameter was usually placed inside the “plate”. They called it "tympanum". On its surface there are also notches, a scale, lines and points of the celestial sphere. And all of them are visible in stereographic projection. In the very center of this disk the celestial pole is marked; on the sides there are also circles of the great circle of the celestial sphere. There are also points of the southern and northern tropics, which serve as peculiar boundaries for the second disk.

On top of the second disc, or “tympanum,” is placed a small openwork lattice, called "spider". There are points on it that coincide with the location of the brightest stars in the sky. They can also be viewed in stereographic projection. This grid also has a special scale, the zodiac circle.

The device also holds several more data disks and is equipped with a hairsight or alidade. It has arrows and a rotary key that activates the device. All parts are attached to the main disk using a thin central axis.

Where was the astrolabe used?

The measurements obtained as a result of using this device were used in drawing up horoscopes, astronomy, mathematics, and physics. Some types of devices were modernized and played the role of a compass for sailors. Using this tool it was interesting to navigate in space and time. This is all an astrolabe.

A few words about stereographic projection

For the first time, one could hear about such a concept as stereographic projection from Claudius Ptolemy. It was he who described the process itself in his work called “Planispherium”. This is a three-dimensional image transferred to a sphere with one punctured point on a suitable plane.

Where can I find?

Today, the astrolabe can be purchased on virtual platforms and auctions, in souvenir shops, at flea markets and museums. It is difficult to make an astrolabe with your own hands. Here you need to understand mathematics, have experience in drawing and be able to correctly take the necessary measurements. After all, the veracity of the final result of the study will depend on how accurately the parameters are set on the device.

How to use an astrolabe?

To start working with the device, you need to pick it up. Using it you can measure the height of the Sun or one of the most bright stars. On final result, as a rule, indicates a ruler, or alidade. Then, the spider mesh rotates. In this case, the ecliptic points indicated on the device coincided with the image of the almucantarate (the smallest circle of the celestial sphere).

When correct use on front side device you will see a stereographic image of our sky. And then you can determine the current time and create an up-to-date horoscope.

What types of devices are there?

There are several varieties of this device. Among them, we highlight the following names of astrolabes:

Shuttle-shaped.
Perfect.
Universal.
Spherical.
Observant.
Linear.
Marine.

The shuttle-shaped device has a central and middle disk. The second largest circle depicts the ecliptic data and the meanings of the stars. The moving part of the device contains almucantarate and a horizon point.

The perfect device was invented by al-Saghani. Unlike other similar devices, when developing this one, a certain arbitrary mark in the celestial sphere was taken as the reporting point. The circles here contained conic sections and straight lines.

The universal device was created by al-Khojandi. As a point of reference, he took center point equinox. The spherical headset is presented in the form of a sphere. The linear astrolabe was invented by Sharaf ad-Din al-Tusi. This is a kind of rod with a scale and reticle. Finally, the naval device was developed in the 15th century. It is a kind of observation device. However, it is not at all intended to perform analog calculations.

The astrolabe is one of the oldest astronomical instruments, dating back to Ancient Greece. This ancient instrument was created more than two thousand years ago, when people believed that the Earth was the center of the Universe.

The astrolabe is sometimes called the very first computer. Undoubtedly, this is a device with the deepest mystery and beauty, and we will now try to learn its secrets.

The first astrolabe appeared in Ancient Greece. Vitruvius in his writing “Ten Books on Architecture”, talking about astronomical instrument, called the “spider,” says that it was “invented by the astronomer Eudoxus, while others say Apollonius.” One of the main parts of this instrument was a drum, where the sky with the zodiac circle was drawn.

The final type of astrolabe was developed in the 4th century. n. e. Thus, in Alexandria, almost three hundred years after Ptolemy, the mathematician and philosopher Hypatia was condemned by Christian society for satanic rituals, including, among other things, the use of an astrolabe. She was executed in 415 AD. Her student, Theon of Alexandria, left behind copies of notes on the use of the astrolabe.

After the death of Hypatia and after the fall of the Roman Empire, Europe “lost” the astrolabe. Most of the ancient Greek knowledge was lost in Western Europe, whose population regarded ancient Greek (and therefore atheist) technology with great suspicion. However, it was carefully guarded by adherents of Islam; their use of the astrolabe is confirmed by many facts. Without Spain and its Islamic religion, the Renaissance would never have come. Most of the ancient Greek texts found have been translated into Arabic. They were later translated into Latin, and the astrolabe was then reintroduced to the vast majority of Europeans.

Scientists of the Islamic East improved the astrolabe and began to use it not only to determine the time and duration of day and night, but also to carry out some mathematical calculations and for astrological predictions. There are many known works of medieval Islamic authors about various designs and the use of the astrolabe.

These are the books of al-Khorezmi, al-Astrulabi, az-Zarqali, as-Sijizi, al-Fargani, as-Sufi, al-Biruni, Nasir ad-Din at-Tusi and others.

Since the 12th century, astrolabes became known in Western Europe, where they first used Arabic instruments, and later began to make their own according to Arabic models. In the 16th century they began to be made based on their own calculations in order to be used in European latitudes.

The astrolabe reached the peak of its popularity in Europe during the Renaissance, in the 15th-16th centuries; along with the armillary sphere, it was one of the main tools for astronomical education.

Knowledge of astronomy was considered the basis of education, and the ability to use an astrolabe was a matter of prestige and a sign of appropriate education. European masters, like their Arab predecessors, paid great attention decoration, so that astrolabes became fashion items and collectibles at royal courts.

It would be pointless to describe exactly how the astrolabe works - it’s best if you see it with your own eyes.

Shuttle-shaped astrolabe.

As al-Biruni wrote, the design of this astrolabe, invented by al-Sijizi, comes “from the conviction of some people that the ordered movement of the Universe belongs to the Earth, and not to the celestial sphere.” The ecliptic and stars are depicted on its tympanum, and the horizon and almucantarates are depicted on the movable part.

The photo shows an Arabian astrolabe 1090, from the collection of the National Museum of American.

The perfect astrolabe.

In this astrolabe, invented by al-Saghani, the center of projection is not the north pole of the world, but an arbitrary point on the celestial sphere. In this case, the main circles of the sphere are depicted on the tympanum no longer by circles and straight lines, but by circles and conical sections.

Universal astrolabe.

In this astrolabe, invented by al-Zarqali, one of the equinox points is taken as the design center. In this case, the celestial equator and the ecliptic are depicted on the tympanum by straight lines. The tympanum of this astrolabe, unlike the tympanums of ordinary astrolabes, is suitable for any latitude. The functions of the spider of an ordinary astrolabe here are performed by a ruler rotating around the center of the tympanum and called the “moving horizon”.

Spherical astrolabe.

The celestial sphere is represented in this astrolabe as a sphere, and its spider is also spherical.

Observational astrolabe.

This astrolabe is a combination of an armillary sphere and a regular astrolabe, embedded in a ring representing the meridian.

Linear astrolabe.

This astrolabe, invented by Sharaf al-Din al-Tusi, is a rod with several scales, with sighting threads attached to it.

Marine astrolabe.

This device, invented by Portuguese craftsmen at the beginning of the 15th century, is a purely observational device and is not intended for analog calculations.

Marine astrolabe.

The photo shows an astrolabe-quadrant, 1325.

Modern encyclopedias say that this device is designed to determine the latitude of a place. In fact, the functions of the astrolabe are much more diverse: it can rightfully be called the computer of a medieval astronomer. Exact number most likely no one can name the functions of the astrolabe, since different types astrolabe could be performed different kinds works Back in the 10th century, the Arab scholar al-Sufi wrote a detailed treatise consisting of 386 chapters, in which he listed 1000 ways to use the astrolabe.

Perhaps he exaggerated slightly, but not by much. After all, with the help of this unique tool it was possible:

Convert the ecliptic coordinates of stars or the Sun into horizontal ones (i.e. determine their altitudes and azimuths);

Using observations of the stars and the Sun through a special viewfinder, determine the latitude of a place, directions to different cities (mainly to calculate the direction to Mecca), determine the time of day, determine sidereal time;

Determine the moments of sunrise and sunset, i.e. the beginning and end of the day, as well as the moments of star rise, and if there were ephemerides, then of the planets; determine the ascending and setting degrees of the ecliptic, i.e. ascendant and descendant, build horoscope houses;

Determine the latitude of an area by measuring the height of the Sun at noon or the heights of the stars at its climax (I’m not sure if this was done often, since using an astrolabe for this purpose is like shooting sparrows with a cannon);

Solve purely earthly problems, such as measuring the depth of a well or the height of an earthly object; and also calculate trigonometric functions(sines, cosines, tangents, cotangents).

Convert between three coordinate systems - equatorial (right ascension and declination), ecliptic (longitude, latitude) and horizontal (azimuth, altitude), and much, much more...

This is how the traditional planispheric astrolabe, usually made of brass, was constructed:

The body most often had a thickness of about 6 mm and a diameter of 15–20 cm (for the largest astrolabes it was up to 50 cm). Although more substantial instruments with a diameter of 30-40 cm were often found, a giant specimen of 85 cm in diameter was known, and, conversely, miniature pocket versions with a diameter of only 8 cm. The fact is that its accuracy directly depended on the size of the astrolabe.

The photo shows an example of how to assemble a simple astrolabe.

In the photo, the Astrolabe by Mahmud ibn Shawka al-Baghdadi 1294-1295 diameter - 96 mm. From the collection of the National Maritime Museum, London

During the heyday of the Arab world, time was measured during the day using a sundial, and at night using a water or sand clock. The astrolabe made it possible to reconcile these watches. To do this, it was necessary to observe the height of the Sun during the day, and at night - one of the bright stars marked on the “spider” of the astrolabe. An interesting device based on the same astrolabe, which can be called a prototype of a mechanical watch, was developed by the famous Arab scientist Al-Biruni. He proposed an astrolabe diagram that automatically showed mutual arrangement Sun and Moon, i.e. lunar phase. The instrument had double body, inside which the gears were fixed. If you rotate the outer disk at a certain speed, you can see the change in the window lunar phases. Later, astrolabes appeared, equipped with gears that simulated the movement of planetary spheres. True, at that time there was no reliable mechanical drive, so the device was fully implemented only in medieval Europe, when the weight and spring drives were invented. And the first mechanical watches, often installed on towers cathedrals in Europe, for a long time were made in the form of astrolabes.

And this is not surprising - after all, complex Arabic astrolabes have turned into real works of art. The star pointers looked not just pins, but spirals and curls in the shape of leaves. The circumference of the instrument was inlaid precious stones and sometimes finished with gold and silver. And all because often a court astrologer would appear with an astrolabe before the menacing eyes of some vizier or shah. An excellent instrument gave weight to the astrologer’s predictions, and not only the fate of the predictor himself depended on this, but also the development of astronomy, more often called then simply the science of the stars.

Pictured is a Persian astrolabe from 1223.

The incident that allegedly happened to Biruni became a legend. One day, an insidious ruler decided to deal with the unwanted scientist and demanded from him an answer to the question: “Which door - northern or southern - will he leave the hall from?” After performing a series of manipulations with the astrolabe, the resourceful Biruni replied that it would be cut through new door. The answer turned out to be correct. But more often than not, rulers were generous to their court astrologers, allocating money for the construction of observatories and the creation of all kinds of zijs - ephemeris tables. All this led, albeit to a small extent, to progress in astronomy.

Pictured is a French astrolabe from the late 16th - early 17th centuries.

The modern descendant of the astrolabe is the planisphere - a movable map of the starry sky, used for educational purposes.

December 1st, 2011

This ancient instrument was created more than two thousand years ago, when people believed that the Earth was the center of the Universe. The astrolabe is sometimes called the very first computer. Undoubtedly, this is a device with the deepest mystery and beauty

The first astrolabe appeared in Ancient Greece. Vitruvius, in his writing “Ten Books on Architecture,” talking about an astronomical instrument called a “spider,” says that it was “invented by the astronomer Eudoxus, while others say Apollonius.” One of the main parts of this instrument was a drum, where the sky with the zodiac circle was drawn.

Stereographic projection was described in the 2nd century AD. e. Claudius Ptolemy in his work “Planispherium”. However, Ptolemy himself called another instrument “astrolabon” - the armillary sphere. The final type of astrolabe was developed in the 4th century. n. e. Thus, in Alexandria, almost three hundred years after Ptolemy, the mathematician and philosopher Hypatia was condemned by Christian society for satanic rituals, including, among other things, the use of an astrolabe. She was beaten, raped and executed in 415 AD. Her student, Theon of Alexandria, left behind copies of notes on the use of the astrolabe.

After the death of Hypatia, Europe "lost" the astrolabe after the fall of the Roman Empire. Most ancient Greek knowledge was lost in Western Europe, whose population regarded ancient Greek (and therefore atheist) technology with great suspicion. However, it was carefully guarded by adherents of Islam; their use of the astrolabe is confirmed by many facts. Without Spain and its Islamic religion, the Renaissance would never have come. Most of the ancient Greek texts found have been translated into Arabic. They were later translated into Latin, and the astrolabe was then reintroduced to the vast majority of Europeans.

Scientists of the Islamic East improved the astrolabe and began to use it not only to determine the time and duration of day and night, but also to carry out some mathematical calculations and for astrological predictions. There are many works by medieval Islamic authors about various designs and uses of the astrolabe.
These are the books of al-Khorezmi, al-Astrulabi, az-Zarqa, al-Sijizi, al-Fargani, al-Sufi, al-Biruni, Nasir ad-Din at-Tusi and others.

The astrolabe reached its peak of popularity in Europe during the Renaissance, in the 15th-16th centuries; along with the armillary sphere, it was one of the main tools for astronomical education.

Knowledge of astronomy was considered the basis of education, and the ability to use an astrolabe was a matter of prestige and a sign of appropriate education. European craftsmen, like their Arab predecessors, paid great attention to artistic design, so that astrolabes became fashion items and collectibles at royal courts.

It would be pointless to describe exactly how the astrolabe works - it is best if you see it with your own eyes.

Shuttle-shaped astrolabe.

Pictured is an Arabian astrolabe 1090, from the collection of the National Museum of American

The perfect astrolabe. In this astrolabe, invented by al-Saghani, the center of projection is not the north pole of the world, but an arbitrary point on the celestial sphere. In this case, the main circles of the sphere are depicted on the tympanum no longer by circles and straight lines, but by circles and conical sections.

Universal astrolabe. In this astrolabe, invented by al-Zarqali, one of the equinox points is taken as the design center. In this case, the celestial equator and the ecliptic are depicted on the tympanum by straight lines. The tympanum of this astrolabe, unlike the tympanums of ordinary astrolabes, is suitable for any latitude. The functions of the spider of an ordinary astrolabe here are performed by a ruler rotating around the center of the tympanum and called the “moving horizon”.

Spherical astrolabe. The celestial sphere is represented in this astrolabe as a sphere, and its spider is also spherical.

Observational astrolabe. This astrolabe is a combination of an armillary sphere and a regular astrolabe, embedded in a ring representing the meridian.

Linear astrolabe. This astrolabe, invented by Sharaf al-Din al-Tusi, is a rod with several scales, with sighting threads attached to it.

Marine astrolabe. This device, invented by Portuguese craftsmen at the beginning of the 15th century, is a purely observational device and is not intended for analog calculations.

nautical astrolabe.

In the photo, Astrolabe-quadrant, 1325g

Modern encyclopedias say that this device is designed to determine the latitude of a place. In fact, the functions of the astrolabe are much more diverse: it can rightfully be called the computer of a medieval astronomer. Most likely, no one will be able to name the exact number of functions of the astrolabe, since different types of astrolabes could perform different types of work. Back in the 10th century, the Arab scholar al-Sufi wrote a detailed treatise consisting of 386 chapters, in which he listed 1000 ways to use the astrolabe. Perhaps he exaggerated slightly, but not by much. After all, with the help of this unique tool it was possible:

recalculate the ecliptic coordinates of stars or the Sun into horizontal ones (i.e. determine their altitudes and azimuths);
using observations of the stars and the Sun through a special viewfinder, determine the latitude of a place, directions to different cities (mainly to calculate the direction to Mecca), determine the time of day, determine sidereal time;
determine the moments of sunrise and sunset, i.e. the beginning and end of the day, as well as the moments of star rise, and if there were ephemerides, then of the planets; determine the ascending and setting degrees of the ecliptic, i.e. ascendant and descendant, build horoscope houses;

determine the latitude of an area by measuring the height of the Sun at noon or the heights of the stars at its climax (I’m not sure if this was done often, since using an astrolabe for this purpose is reminiscent of shooting sparrows from a cannon);
solve purely earthly problems, such as measuring the depth of a well or the height of an earthly object; and also calculate trigonometric functions (sines, cosines, tangents, cotangents).
make transformations between three coordinate systems - equatorial (right ascension and declination), ecliptic (longitude, latitude) and horizontal (azimuth, altitude), and much, much more...

This is how the traditional planispheric astrolabe, usually made of brass, was constructed.

The body most often had a thickness of about 6 mm and a diameter of 15 - 20 cm (for the largest astrolabes - up to 50 cm). Although more substantial instruments with a diameter of 30-40 cm were often found, a giant specimen of 85 cm in diameter was known, and, conversely, miniature pocket versions with a diameter of only 8 cm. The fact is that its accuracy directly depended on the size of the astrolabe.

The photo shows an example of how to assemble a simple astrolabe.

IN THE PHOTO Astrolabe by Mahmud ibn Shawka al-Baghdadi 1294-1295 diameter - 96 mm. From the collection of the National Maritime Museum, London

During the heyday of the Arab world, time was measured during the day using a sundial, and at night using a water or sand clock. The astrolabe made it possible to reconcile these watches. To do this, it was necessary to observe the height of the Sun during the day, and at night - one of the bright stars marked on the “spider” of the astrolabe. An interesting device based on the same astrolabe, which can be called a prototype of a mechanical watch, was developed by the famous Arab scientist Al-Biruni. He proposed an astrolabe diagram that automatically showed the relative positions of the Sun and Moon, i.e. lunar phase. The tool had a double body, inside of which gears were fixed. If the outer disk was rotated at a certain speed, the change in lunar phases could be observed in the window. Later, astrolabes appeared, equipped with gears that simulated the movement of planetary spheres. True, at that time there was no reliable mechanical drive, so the device was fully realized only in medieval Europe, when weight and spring drives were invented. And the first mechanical clocks, often installed on the towers of cathedrals in Europe, were made in the form of astrolabes for a long time.

And this is not surprising - after all, complex Arabic astrolabes have turned into real works of art. The star pointers looked not just pins, but spirals and curls in the shape of leaves. The circumference of the instrument was inlaid with precious stones and sometimes trimmed with gold and silver. And all because often a court astrologer would appear with an astrolabe before the menacing eyes of some vizier or shah. An excellent instrument gave weight to the astrologer’s predictions, and not only the fate of the predictor himself depended on this, but also the development of astronomy, more often called then simply the science of the stars.

Pictured is a Persian astrolabe 1223

The incident that allegedly happened to Biruni became a legend. One day, an insidious ruler decided to deal with an unwanted scientist and demanded from him an answer to the question: “Which door - northern or southern - will he leave the hall from?” After performing a series of manipulations with the astrolabe, the resourceful Biruni replied that a new door would be cut. The answer turned out to be correct. But more often than not, rulers were generous to their court astrologers, allocating money for the construction of observatories and the creation of all kinds of zijs - ephemeris tables. All this led, albeit to a small extent, to progress in astronomy.

In the photo is a French astrolabe from the late 16th - early 17th centuries.

The modern descendant of the astrolabe is the planisphere - a movable map of the starry sky, used for educational purposes.

This astronomical instrument has made such a long journey through the centuries, without losing its magical charm in our age of computers and powerful telescopes.

Today, things marked by time are in fashion: antiques, various products in and retro. A special chic to the interior based on such decor is given by tools and appliances, which have now lost their relevance, but add a certain flavor and create an atmosphere. These include, for example, a gramophone or a cast iron iron. However, we will not talk about these fairly common units. The focus of the article is the answer to the question of what astrolabes are. These ancient instruments are also now experiencing a rebirth as attributes of styles with a retro or steampunk bent.

Multifunctional tool

The astrolabe, photos of which give a small idea of the use of the object for a person not related to astronomy, is simply a beautiful and unusual instrument. However, it has a very specific function. A device was invented for measuring distances from the Earth's surface to stars and planets, which were then used for orientation, determining coordinates, and also astrological predictions. With the help of an ancient astronomical instrument, it was possible to calculate what stars would be there when the Sun would set or rise, and what time it was.

Origin

Already in the second century BC, scientists knew what astrolabes were. The instrument appeared on the territory of Ancient Greece, where it was supplemented and somewhat modified over several centuries. The astrolabe, a photo of which can be found in the article, was brought into this form by Theon of Alexandria in the 4th century. n. e.

Despite its Greek origin, the astrolabe owes a lot to the Arabs. If it weren’t for them, most likely, such an instrument would not have reached us.

Persecution of the Church

The Middle Ages were not the most fertile time for the development of science in Europe. Everything worldly, one way or another trying to explain the world without referring to the concept of God, was declared false and dangerous. After the death of the Roman Empire, the astrolabe was forgotten for centuries in the West. At the same time, a new round of history for the device began in the vastness of Arab countries, where scientists expanded its capabilities.

Update

Eastern masters made their own adjustments to the understanding of what astrolabes are. Now these instruments were used not only for astronomical calculations, terrain orientation and time calculation. Arab astrolabes made it possible to make complex mathematical calculations and predict fate using the stars.

In the vastness of Persia, India and other countries, many books were created containing a description of the structure and use of the instrument for various purposes. All prominent scientists had this device. Both then and later, already in Europe, the science of the stars was revered as the basis of any knowledge, and the astrolabe was a symbol of wisdom. Every astrologer who served as an adviser at the Sultan's court knew how to use the instrument.

Device

The design of the astrolabe consisted of several parts. The base is a circle of brass or copper with a rim around the edge, a hole and a hanging ring in the middle. The latter helped to correctly place the device relative to the horizon line. Along the entire length of the circle there were marks - a scale with divisions, degrees or hours printed on it. The situation of large cities was also often noted.

The so-called tympanum, a disk with a stereographic projection of the starry sky, was placed on the base of the astrolabe. The celestial pole, the north pole and the zenith point with azimuthal circles were marked on it. There were several tympanums for different areas. Each was distinguished by the peculiarities of the position of the zenith point and the horizon line, valid at a given latitude.

A lattice was placed on top of the disk with a projection of the sky, which, due to its structural features, was called a “spider”. It was equipped with pointers to help determine the location. The arrows were often made in the form of elegant leaves or curls, making the whole structure not only convenient in functional terms, but also delivering

Back in Europe

Centuries later, the West again learned what astrolabes are, thanks to the study of the works of Eastern scientists. Europeans began to use Arabic instruments, and then made their own. New examples were also decorated in the manner of their eastern counterparts. Soon, astrolabes became striking specimens in the collections of nobles.

Today this device is a symbol of mysteries: the astrolabe is more often associated in the minds of people with the predictions of astrologers than with the research of astronomers. For example, the device may be associated with a name that many people now know - Astrolabe gave the name to one of the companies that send out dubious predictions of its authorship. But despite such twists of fate, the instrument for most today is part of the history of astronomy, interesting symbol a bygone era and a beautiful attribute.

Scientists of the Islamic East improved the astrolabe and began to use it not only to determine the time and duration of day and night, but also to carry out some mathematical calculations and for astrological predictions. There are many works by medieval Islamic authors about various designs and uses of the astrolabe.
These are the books of al-Khorezmi, al-Astrulabi, az-Zarqali, as-Sijizi, al-Fargani, as-Sufi, al-Biruni, Nasir ad-Din at-Tusi and others.

It would be pointless to describe exactly how the astrolabe works - it’s best if you see it with your own eyes.

Shuttle-shaped astrolabe.

Pictured is an Arabian astrolabe 1090, from the collection of the National Museum of American

Spherical astrolabe. The celestial sphere is represented in this astrolabe as a sphere, and its spider is also spherical.

Observational astrolabe. This astrolabe is a combination of an armillary sphere and a regular astrolabe, embedded in a ring representing the meridian.

Linear astrolabe. This astrolabe, invented by Sharaf al-Din al-Tusi, is a rod with several scales, with sighting threads attached to it.

Marine astrolabe. This device, invented by Portuguese craftsmen at the beginning of the 15th century, is a purely observational device and is not intended for analog calculations.

In the photo, Astrolabe-quadrant, 1325g

Modern encyclopedias say that this device is designed to determine the latitude of a place. In fact, the functions of the astrolabe are much more diverse: it can rightfully be called the computer of a medieval astronomer. Most likely, no one will be able to name the exact number of functions of the astrolabe, since different types of astrolabes could perform different types of work. Back in the 10th century, the Arab scholar al-Sufi wrote a detailed treatise consisting of 386 chapters, in which he listed 1000 ways to use the astrolabe. Perhaps he exaggerated slightly, but not by much. After all, with the help of this unique tool it was possible:

recalculate the ecliptic coordinates of stars or the Sun into horizontal ones (i.e. determine their altitudes and azimuths);
using observations of the stars and the Sun through a special viewfinder, determine the latitude of a place, directions to different cities (mainly to calculate the direction to Mecca), determine the time of day, determine sidereal time;
determine the moments of sunrise and sunset, i.e. the beginning and end of the day, as well as the moments of star rise, and if there were ephemerides, then of the planets; determine the ascending and setting degrees of the ecliptic, i.e. ascendant and descendant, build horoscope houses;

determine the latitude of an area by measuring the height of the Sun at noon or the heights of the stars at its climax (I’m not sure if this was done often, since using an astrolabe for this purpose is reminiscent of shooting sparrows from a cannon);
solve purely earthly problems, such as measuring the depth of a well or the height of an earthly object; and also calculate trigonometric functions (sines, cosines, tangents, cotangents).
make transformations between three coordinate systems - equatorial (right ascension and declination), ecliptic (longitude, latitude) and horizontal (azimuth, altitude), and much, much more...

This is how the traditional planispheric astrolabe, usually made of brass, was constructed.

The photo shows an example of how to assemble a simple astrolabe.

IN THE PHOTO Astrolabe by Mahmud ibn Shawka al-Baghdadi 1294-1295 diameter - 96 mm. From the collection of the National Maritime Museum, London

During the heyday of the Arab world, time was measured during the day using a sundial, and at night using a water or sand clock. The astrolabe made it possible to reconcile these watches. To do this, it was necessary to observe the height of the Sun during the day, and at night - one of the bright stars marked on the “spider” of the astrolabe. An interesting device based on the same astrolabe, which can be called a prototype of a mechanical watch, was developed by the famous Arab scientist Al-Biruni. He proposed an astrolabe diagram that automatically showed the relative positions of the Sun and Moon, i.e. lunar phase. The tool had a double body, inside of which gears were fixed. If the outer disk was rotated at a certain speed, the change in lunar phases could be observed in the window. Later, astrolabes appeared, equipped with gears that simulated the movement of planetary spheres. True, at that time there was no reliable mechanical drive, so the device was fully realized only in medieval Europe, when weight and spring drives were invented. And the first mechanical clocks, often installed on the towers of cathedrals in Europe, were made in the form of astrolabes for a long time.

And this is not surprising - after all, complex Arabic astrolabes have turned into real works of art. The star pointers looked not just pins, but spirals and curls in the shape of leaves. The circumference of the instrument was inlaid with precious stones and sometimes trimmed with gold and silver. And all because often a court astrologer would appear with an astrolabe before the menacing eyes of some vizier or shah. An excellent instrument gave weight to the astrologer’s predictions, and not only the fate of the predictor himself depended on this, but also the development of astronomy, more often called then simply the science of the stars.

Pictured is a Persian astrolabe 1223

The incident that allegedly happened to Biruni became a legend. One day, an insidious ruler decided to deal with the unwanted scientist and demanded from him an answer to the question: “Which door - northern or southern - will he leave the hall from?” After performing a series of manipulations with the astrolabe, the resourceful Biruni replied that a new door would be cut. The answer turned out to be correct. But more often than not, rulers were generous to their court astrologers, allocating money for the construction of observatories and the creation of all kinds of zijs - ephemeris tables. All this led, albeit to a small extent, to progress in astronomy.