The astrolabe is an ancient astronomical instrument. Astrolabe What does an astrolabe measure?

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 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

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 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 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 masters, like their Arab predecessors, paid great attention decoration, so that astrolabes became fashion items and collectibles at royal courts.

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:

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

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This ancient instrument was invented more than two thousand years ago - in an era when people considered the Earth to be the center of the Universe. The astrolabe is often called the first computer, but no matter how controversial this statement may sound, there is no doubt that this instrument is surrounded by an aura of mystery and mystical beauty.

2. So what was the astrolabe intended for and how did it help our ancestors? Firstly, it made it possible to calculate quantities such as time based on the position of the sun and stars in the sky. Just like with a computer, you input information and the output is output. Typically, astrolabes were made of brass and were about 15 centimeters in diameter. But as you can see in the photographs, there were also larger specimens.

3. On front side a starry sky was drawn, and on it were 20 of the most bright stars. The first question that comes to mind is: if the ancients believed that the Earth was at the center of the Universe, could these devices work correctly? After all, in fact, the Earth revolves around the Sun. Our ancestors, however, knew the relative sizes of the Earth and the Sun and the approximate distance between them. And based only on what we can see, between geo and heliocentric systems there is no difference, at least from a mathematical point of view.

4. The moving parts were installed opposite the divisions of the time of day and date, and the sky map corresponding to this moment was shown on the front side of the instrument. What's the point of this? With the help of the astrolabe, many astronomical problems were solved. The simplest is, of course, determining time. People could also calculate the time of sunrise and sunset. In addition, the device made it possible to determine the direction; so the astrolabe was an invaluable “compass” for Muslim scholars who were heading to Mecca.

5. Until the late Middle Ages, the astrolabe was one of the main instruments of astronomy. Over the centuries, many astrolabes have been invented, but the most common is the planispherical one, in which the celestial sphere is projected onto the plane of the equator. The principles of such a projection were discussed 150 years before the birth of Christ, however, it is believed that the first device was created much later. In fact, what we call the astrolabe was already in the service of astronomers by the year 400.

6. The astrolabe, like many other things, came from ancient Greece. It is known that the Greeks studied astrolabe projections two hundred years before our era. The theory was subsequently expounded by Hippocrates, who was born in Nicaea in Asia Minor. What is the connection with Greece? He conducted all his research on the island of Rhodes (Greece), where he wrote many works on trigonometry.

7. But when did the theory find physical embodiment? When was the first time a person picked up an astrolabe? The first mention of a device resembling an astrolabe is found in Marcus Vitruvius Polion, who died in 26 BC. He describes a clock in Alexandria that had a rotating disk depicting stars. Maybe this was the ancestor of the astrolabe?

8. Although there is no direct evidence for this, Claudius Ptolemy (died 168 AD) in his manuscripts (from his library in Alexandria) mentions a certain device very similar to the one we are talking about now. And since he wrote a lot about the geometry of the Earth-Sun system, which is the basis for the operation of the astrolabe, it would be fair to assume that he was also associated with its creation. Most astronomical historians consider the year 150 AD. date of appearance of the first astrolabe.

9. Times are changing. And now, three centuries later (and again in Alexandria), the Christian community of the city accuses Hypatia, a woman who studied mathematics and philosophy, of worshiping Satan. Among other objects for her “rituals,” an astrolabe is also mentioned... The crowd attacked her in broad daylight, she was raped and executed. This happened in 415 AD. Her student, Theon of Alexandria, left many records of the use of the astrolabe. However, its use in the West was banned for almost a thousand years.

10. It is interesting that after the death of Hypatia, the West finally lost the astrolabe when the Roman Empire fell, and the Dark Ages (formerly the Middle Ages) began for Europe. Much was lost from ancient Greek science to Western Europe. Its inhabitants began to treat Hellenistic - pagan - technologies with great suspicion. However, they survived in the Islamic world, where much evidence of their use and development has been found.

11. The Moors of Andalusia returned the astrolabe to Europe. Perhaps without the Spanish Arabs the Renaissance would never have come. To be fair, the knowledge of Arab Andalusia in the twelfth century spread throughout Europe. And many Western minds flocked to cities like Cordoba, which they considered centers of "lost knowledge." Greek texts, which could no longer be found in Europe, existed in such places in Arabic. There the books were translated into Latin, and the astrolabe was again presented to the European public.

12. And although these devices were replaced by more advanced instruments in the mid-seventeenth century, the astrolabe is still used to this day - mainly for teaching astronomy. And not only because it is of great historical value, it is also used for its intended purpose. And yet now the astrolabe, according to by and large, is a beautiful and mysterious instrument of ancient astronomers.

Secrets and history ancient invention. Astrolabe

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 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 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 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-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 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.

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 almucantarata 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.
Astrolabe. Secrets and history of an ancient invention

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. 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, 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 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 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.

The astrolabe is one of the first instruments with the help of which the height of the Sun or stars was determined, and from them the coordinates of a point on the surface of the earth.

How does an astrolabe work?

The height of the Sun was determined using a ruler called an “alidade”. Then the observer turned the “spider” so that the desired points on the ecliptic and on the small circle, which is called “almucantarat,” coincided. Thanks to this action on outside The device produced a stereographic projection of the sky at a given moment.

Originally from antiquity

In that era there were several types of similar instruments; they were not yet quite similar to the astrolabes of later eras. In its more or less modern form this instrument was made by Theon. This happened already in our era, in the fourth century. Treatises on this instrument date back to the same era. The astrolabe served as a tool for telling time.

From Greece the device came to the East. Arab scientists used it not only for astronomical, but also for mathematical purposes. In Western Europe, Arab astrolabes were used during the Crusaders. Then the Europeans began making such instruments themselves. Scientific works also appeared. One of the treatises was written by the great English Geoffrey Chaucer.

Basics