All Topics  
Astrolabe

 

 

 

 

 

Astrolabe


 
 


The astrolabe is a historical astronomical instrumentMeasuring instrument Summary

In physics and engineering, measurement is the activity of comparing physical quantities of real-world objects and events....
 used by classical astronomersFacts About Astronomy

Astronomy is the science of celestial objects and phenomena that originate outside the Earth's atmosphere ....
, navigators, and astrologers. Its many uses included locating and predicting the positions of the SunSun

|+ The Sun   |+|-| colspan="2" align="center" | |-...
, MoonMoon

The Moon is Earth's only natural satellite....
, planets and starsFacts About STARS

STARS can mean:*Shock Trauma Air Rescue Society...
; determining local time given local latitude and vice-versa; surveying; and triangulationTriangulation

In trigonometry and elementary geometry, triangulation is the process of finding coordinates and distance to a point by calc...
.

In the medieval Islamic worldIslamic Golden Age Summary

During the Islamic Golden Age philosophers, scientists and engineers of the Islamic world contributed enormously to technolo...
, they were used primarily for astronomical studiesIslamic astronomy

In its origins and development, Islamic astronomy closely parallels the genesis of other Islamic sciences in its assimilation of f...
, as well as in other areas as diverse as astrologyIslamic astrology

Islamic astrology, in Arabic ilm al-nujum or ilm al-falak is the study of the heavens by early Muslims....
, navigationMariner's astrolabe

The mariner's astrolabe, also called sea astrolabe, is not an astrolabe proper, but rather a graduated circle with an ...
, surveyingSurveying

Surveying is the technique and science of accurately determining the terrestrial or three-dimensional space position of poin...
, timeTime

Two distinct views exist on the meaning of time....
keeping, Salah prayerPrayer

Prayer is an active effort to communicate with a deity or spirit, including a monotheist God, Saints, gods within a pantheon...
s, and QiblaQibla

Qibla is an Arabic word for the direction that should be faced when a Muslim prays....
. Astrologers of the European nations used astrolabes to construct horoscopes.

There is often confusion between the astrolabe and the mariner's astrolabeMariner's astrolabe

The mariner's astrolabe, also called sea astrolabe, is not an astrolabe proper, but rather a graduated circle with an ...
. While the astrolabe could be useful for determining latitude on land, it was an awkward instrument for use on the heaving deck of a ship or in wind.






Discussion
Ask a question about 'Astrolabe'
Start a new discussion about 'Astrolabe'
Answer questions from other users
Full Discussion Forum





Recent Posts









Encyclopedia




The astrolabe is a historical astronomical instrumentMeasuring instrument Summary

In physics and engineering, measurement is the activity of comparing physical quantities of real-world objects and events....
 used by classical astronomersFacts About Astronomy

Astronomy is the science of celestial objects and phenomena that originate outside the Earth's atmosphere ....
, navigators, and astrologers. Its many uses included locating and predicting the positions of the SunSun

|+ The Sun   |+|-| colspan="2" align="center" | |-...
, MoonMoon

The Moon is Earth's only natural satellite....
, planets and starsFacts About STARS

STARS can mean:*Shock Trauma Air Rescue Society...
; determining local time given local latitude and vice-versa; surveying; and triangulationTriangulation

In trigonometry and elementary geometry, triangulation is the process of finding coordinates and distance to a point by calc...
.

In the medieval Islamic worldIslamic Golden Age Summary

During the Islamic Golden Age philosophers, scientists and engineers of the Islamic world contributed enormously to technolo...
, they were used primarily for astronomical studiesIslamic astronomy

In its origins and development, Islamic astronomy closely parallels the genesis of other Islamic sciences in its assimilation of f...
, as well as in other areas as diverse as astrologyIslamic astrology

Islamic astrology, in Arabic ilm al-nujum or ilm al-falak is the study of the heavens by early Muslims....
, navigationMariner's astrolabe

The mariner's astrolabe, also called sea astrolabe, is not an astrolabe proper, but rather a graduated circle with an ...
, surveyingSurveying

Surveying is the technique and science of accurately determining the terrestrial or three-dimensional space position of poin...
, timeTime

Two distinct views exist on the meaning of time....
keeping, Salah prayerPrayer

Prayer is an active effort to communicate with a deity or spirit, including a monotheist God, Saints, gods within a pantheon...
s, and QiblaQibla

Qibla is an Arabic word for the direction that should be faced when a Muslim prays....
. Astrologers of the European nations used astrolabes to construct horoscopes.

There is often confusion between the astrolabe and the mariner's astrolabeMariner's astrolabe

The mariner's astrolabe, also called sea astrolabe, is not an astrolabe proper, but rather a graduated circle with an ...
. While the astrolabe could be useful for determining latitude on land, it was an awkward instrument for use on the heaving deck of a ship or in wind. The mariner's astrolabe was developed to address these issues.

A Brief History




An early rudimentary astrolabe was invented in the Hellenistic worldHellenistic civilization

The term Hellenistic was established by the German historian Johann Gustav Droysen to refer to the spreading of Greek cultu...
 in either the first or second centuries BC and is often attributed to HipparchusHipparchus

Hipparchus, the common Latinization of the Greek Hipparchos, can mean:...
. A marriage of the planispherePlanisphere

A planisphere consists of a circular star chart attached at the center of the starchart to an opaque overlay that has a clea...
 and dioptraDioptra

A dioptra is an instrument dating back to ancient Greece, at least 300 BCE....
, the astrolabe was effectively an analog calculator capable of working out several different kinds of problems in spherical astronomy. Theon of AlexandriaTheon of Alexandria

Theon was a scholar and the last director of the Library of Alexandria in the Museion, until it was closed by the patria...
 wrote a detailed treatise on the astrolabe, and argues that PtolemyPtolemy

Claudius Ptolemaeus , known in English as Ptolemy, was a Greek-speaking geographer, astronomer, and astrologer who liv...
 used an astrolabe to make the astronomical observations recorded in the Tetrabiblos.

Brass astrolabes were developed in the medieval Islamic worldIslamic Golden Age

During the Islamic Golden Age philosophers, scientists and engineers of the Islamic world contributed enormously to technolo...
, chiefly as an aid to navigation and as a way of finding the qiblaQibla

Qibla is an Arabic word for the direction that should be faced when a Muslim prays....
, the direction of MeccaMecca

Mecca or Makkah is the capital city of Saudi Arabia's Makkah province, in the historic Hijaz region....
. The first person credited with building the astrolabe in the Islamic world is reportedly the 8th century8th century

The 8th century is the period from 701 - 800 in accordance with the Julian calendar in the Christian Era....
 PersianPersian people

The Persians are an Iranian people who speak the Persian language and share a common culture and history....
 mathematicianIslamic mathematics

In the history of mathematics, "Islamic mathematics" refers to the mathematics developed by mathematicians of the Islamic cu...
 al-Fazari. The mathematical background was established by the ArabArab

The Arabs are predominantly speakers of the Arabic language, rather than a pure ethnic group, mainly found throughout the ...
 astronomerIslamic astronomy

In its origins and development, Islamic astronomy closely parallels the genesis of other Islamic sciences in its assimilation of f...
 al-BattaniAl-Battani

Abu ?Abdullah Mu?ammad ibn Jabir ibn Sinan ar-Raqqi al-?arrani a?-?abi? al-Battani was an Arab astronomer/astrologer and mat...
 in his treatise Kitab az-Zij (ca. 920 AD), which was translated into Latin by Plato TiburtinusPlato Tiburtinus

Plato Tiburtinus was a 12th century Italian mathematician, astronomer and translator who lived in Barcelona....
 (De Motu Stellarum).
The is dated AHIslamic calendar

The Islamic calendar or Muslim calendar is the calendar used to date events in many predominantly Muslim countries, a...
 315. In the Islamic world, astrolabes were used to find the times of sunrise and the rising of fixed stars, to help schedule morning prayers. In the 10th century, al-Sufi first described over 1,000 different uses of an astrolabe, in areas as diverse as astronomyFacts About Astronomy

Astronomy is the science of celestial objects and phenomena that originate outside the Earth's atmosphere ....
, astrology, horoscopeIslamic astrology

Islamic astrology, in Arabic ilm al-nujum or ilm al-falak is the study of the heavens by early Muslims....
s, navigationMariner's astrolabe

The mariner's astrolabe, also called sea astrolabe, is not an astrolabe proper, but rather a graduated circle with an ...
, surveyingSurveying

Surveying is the technique and science of accurately determining the terrestrial or three-dimensional space position of poin...
, timeTime

Two distinct views exist on the meaning of time....
keeping, prayerPrayer

Prayer is an active effort to communicate with a deity or spirit, including a monotheist God, Saints, gods within a pantheon...
, Salah, QiblaQibla

Qibla is an Arabic word for the direction that should be faced when a Muslim prays....
, etc.

ArzachelArzachel

Al-Zarqali,, was a leading Arab mathematician and the foremost astronomer of his time....
 (al-Zarqali) of al-AndalusFacts About Al-Andalus

Al-Andalus was the Arabic name given to those parts of the Iberian Peninsula governed by Muslims from 711 to 1492....
 constructed the first universal astrolabe instrument which, unlike its predecessors, did not depend on the latitudeLatitude

Latitude, usually denoted symbolically by the Greek letter f , gives the location of a place on Earth north or south of the ...
 of the observer, and could be used from anywhere on the Earth. This instrument became known in Europe as the "Saphaea". The astrolabe was introduced to other parts of Europe via Al-AndalusAl-Andalus

Al-Andalus was the Arabic name given to those parts of the Iberian Peninsula governed by Muslims from 711 to 1492....
 in the 11th century11th century

As a means of recording the passage of time, the 11th century was that century which lasted from 1001 to 1100....
. Early Christian recipients of Arab astronomy included Gerbert of Aurillac and Hermannus ContractusHermannus Contractus

Hermannus Contractus was an 11th century scholar, composer, and music theorist....
. The first gearGear

Gears or toothed wheels are positive type drives which are used to transmit motion between two shafts or a shaft and a compo...
ed mechanical astrolabe was later developed by Abi Bakr of Isfahan in 1235.

Peter of MaricourtPeter of Maricourt

Peter of Maricourt was a medieval French scientist who lived in the 13th century, conducted experiments on magnetism and wro...
 in the last half of the thirteenth century also wrote a treatise on the construction and use of a universal astrolabe (Nova compositio astrolabii particularis). However, given the complicated nature of the instrument, it is highly unlikely that any were actually constructed; at least none survive.

The English author Geoffrey ChaucerGeoffrey Chaucer

Geoffrey Chaucer was an English author, poet, philosopher, bureaucrat , and diplomat....
 (ca. 1343–1400) compiled a treatise on the astrolabeTreatise on the Astrolabe

A Treatise on the Astrolabe is a medieval essay on the astrolabe by Geoffrey Chaucer....
 for his son, mainly based on Messahalla. The same source was translated by the French astronomer and astrologer Pelerin de Prusse and others. The first printed book on the astrolabe was Composition and Use of Astrolabe by Cristannus de Prachaticz, also using Messahalla, but relatively original.

In 1370, the first IndiaIndia

India , officially the Republic of India, is a country in South Asia....
n treatise on the astrolabe was written by the JainJainism

Jainism , traditionally known as Jain Dharma , is a religion and philosophy originating in ancient India....
 astronomer Mahendra SuriMahendra Suri

Mahendra Suri was the author of the astronomical text Yantraraja....
.

The first known European metal astrolabe was developed in the 15th century15th century

As a means of recording the passage of time, the 15th century was that century which lasted from 1401 to 1500....
 by RabbiRabbi

Rabbi in Judaism, means "teacher", or more literally "great one"....
 Abraham ZacutoAbraham Zacuto

Abraham Zacuto was a Spanish astronomer, mathematician and historian who served as Royal Astronomer in the 15th Century to K...
 in LisbonLisbon

Lisbon is the capital and largest city of Portugal....
. Metal astrolabes improved on the accuracy of their wooden precursors. In the 15th century15th century

As a means of recording the passage of time, the 15th century was that century which lasted from 1401 to 1500....
, the French instrument-maker Jean Fusoris (ca. 1365–1436) also started selling astrolabes in his shop in ParisParis Overview

native_name = Ville de Paris|common_name = Paris...
, along with portable sundialSundial

A sundial measures time by the position of the sun....
s and other popular scientific gadgetGadget Summary

A gadget or gazza is a device that has a useful specific practical purpose and function....
s of the day.

In the 16th century, Johannes StöfflerFacts About Johannes Stöffler

Johannes Stffler was a German mathematician, astronomer, astrologer, priest, maker of astronomical instruments and professor...
 published Elucidatio fabricae ususque astrolabii, a manual of the construction and use of the astrolabe. Four identical 16th century astrolabes made by Georg HartmannGeorg Hartmann

Georg Hartmann was a German engineer, instrument maker, author, printer, humanist, churchman, and astronomer....
 provide some of the earliest evidence for batch productionBatch production

Batch production is used to produce or process any product in groups that are called batches , as opposed to a continuous pr...
 by division of labor.

Astrolabes and clocks

At first mechanical astronomical clockAstronomical clock

An astronomical clock is a clock with special mechanisms and dials to display astronomical information, such as the relative...
s were influenced by the astrolabe; in many ways they could be seen as clockwork astrolabes designed to produce a continual display of the current position of the sun, stars, and planets. Ibn al-ShatirIbn al-Shatir

Ibn al-Shatir or Ibn ash-Shatir was an Arab Islamic astronomer....
 constructed the earliest astrolabic clock in the early 14th century. At around the same time, Richard of WallingfordRichard of Wallingford

Richard of Wallingford was an English mathematician active in the 14th century, who made major contributions to astronomy an...
's clock (c. 1330) consisted essentially of a star map rotating behind a fixed rete, similar to that of an astrolabe.

Many astronomical clocks, such as the famous clockPrague Orloj

The Prague Astronomical Clock or Prague Orloj is a medieval astronomical clock located in Prague at , the capital of t...
 at Prague, use an astrolabe-style display, adopting a stereographic projection (see below) of the ecliptic plane.

In 1985 Swiss watchmaker Dr. Ludwig Oechslin designed and built an in conjunction with Ulysse NardinUlysse Nardin Summary

Ulysse Nardin is a watch manufacturer founded in 1846 in Le Locle, Switzerland....

Construction


An astrolabe consists of a hollow disk, called the materMater

Mater is a fictional, anthropomorphic tow truck from the Disney/Pixar animated film Cars....
(mother), which is deep enough to hold one or more flat plates called tympans, or climateClime

The seven climes was a notion of dividing the Earth into zones in Classical Antiquity....
s
. A tympan is made for a specific latitude and is engraved with a stereographic projectionStereographic projection

In cartography and geometry, the stereographic projection is a mapping that projects each point on a sphere onto a tangent p...
 of circularCircle

In Euclidean geometry, a circle is the set of all points in a plane at a fixed distance, called the radius, from a fixed poi...
 lines of equal azimuthAzimuth

Azimuth is the horizontal component of a direction , measured around the horizon usually from the north toward the East, i.e...
 and altitudeAltitude

Altitude is the elevation of an object from a known level or datum....
 representing the portion of the celestial sphereCelestial sphere

In astronomy and navigation, the celestial sphere is an imaginary rotating sphere of "gigantic radius", concentric and coaxi...
 which is above the local horizon. The rim of the mater is typically graduated into hours of time, or degrees of arc, or both. Above the mater and tympan, the rete, a framework bearing a projection of the eclipticEcliptic

The ecliptic is the apparent path the Sun traces out along the sky — independent of Earth's rotation — in the co...
 plane and several pointerPointer (rod)

A pointer or pointing stick is a solid rod used to point manually, in the form of a stick, but always finished off or ...
s indicating the positions of the brightest starStar Summary

A star is a massive, compact body of plasma in outer space that is held together by its own gravity and, unlike a planet, is...
s, is free to rotate. Some astrolabes have a narrow rule or label which rotates over the rete, and may be marked with a scale of declinationDeclination

In astronomy, declination is one of the two coordinates of the equatorial coordinate system, the other being either right a...
s.

The rete, representing the skySky

The sky is the part of the atmosphere or of outer space visible from the surface of the earth....
, has the function of a star chartStar chart

A star chart is a map of the night sky....
. When it is rotated, the stars and the eclipticEcliptic

The ecliptic is the apparent path the Sun traces out along the sky — independent of Earth's rotation — in the co...
 move over the projection of the coordinates on the tympan. A complete rotation represents the passage of one day. The astrolabe is therefore a predecessor of the modern planispherePlanisphere

A planisphere consists of a circular star chart attached at the center of the starchart to an opaque overlay that has a clea...
.

On the back of the mater there will often be engraved a number of scales which are useful in the astrolabe's various applications; these will vary from designer to designer, but might include curves for time conversions, a calendarCalendar

A calendar is a system for naming periods of time, typically days....
 for converting the day of the month to the sun's position on the ecliptic, trigonometric scales, and a graduation of 360 degrees around the back edge. The alidadeAlhidade

The alhidade or alidade is the part of a theodolite that rotates around the vertical axis, and that bears the horizont...
is attached to the back face. When the astrolabe is held vertically, the alidade can be rotated and a star sighted along its length, so that the star's altitude in degrees can be read ("taken") from the graduated edge of the astrolabe; hence "astro" = star + "labe" = to take.

See also

  • Antikythera mechanismAntikythera mechanism

    The Antikythera mechanism is an ancient mechanical analog computer designed to calculate astronomical positions....
  • Armillary sphereArmillary sphere

    An armillary sphere is a model of the celestial sphere, invented by Eratosthenes in 255 BC....
  • AstrariumAstrarium

    An astrarium, also called a planetarium, is the mechanical representation of the cyclic nature of astronomical objects...
  • AstrologyAstrology

    Astrology is a group of systems, traditions, and beliefs in which knowledge of the relative positions of celestial bodies an...
  • Astronomical clockFacts About Astronomical clock

    An astronomical clock is a clock with special mechanisms and dials to display astronomical information, such as the relative...
  • CosmolabeCosmolabe

    The cosmolabe was an ancient astronomical instrument resembling the astrolabe, formerly used for measuring the angles betwee...
  • EquatoriumEquatorium

    An Equatorium was a medieval astrometic device used by astronomers....
  • Islamic astronomyIslamic astronomy

    In its origins and development, Islamic astronomy closely parallels the genesis of other Islamic sciences in its assimilation of f...
  • OrreryOrrery

    An orrery is a mechanical device that illustrates the relative positions and motions of the planets and moons in the solar s...
  • PlanetariumPlanetarium

    A planetarium is a theater built primarily for presenting educational and entertaining shows about astronomy and the night s...
  • Prague OrlojPrague Orloj

    The Prague Astronomical Clock or Prague Orloj is a medieval astronomical clock located in Prague at , the capital of t...
  • SextantSextant

    A sextant is a measuring instrument generally used to measure the angle of elevation of a celestial object above the horizon...
  • Sharafeddin TusiSharafeddin Tusi

    Sharafeddin Muzzafar-i Tusi was a Persian mathematician of the Middle Ages....
    , the inventor of the linear astrolabe
  • TorquetumTorquetum

    The Torquetum or Turquet is a medieval astronomical instrument designed to take and convert measurements made in three sets ...


External links

  • at