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The Great Contribution of Islamic Astronomers

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Author Topic: The Great Contribution of Islamic Astronomers  (Read 3668 times)
Bianca
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« Reply #105 on: October 13, 2008, 02:43:30 pm »





                                   

                                    QUADRANT
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Bianca
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« Reply #106 on: October 13, 2008, 02:51:05 pm »










                                              M U R A L   I N S T R U M E N T S






A number of mural instruments (including several different quadrants and sextants) were invented by Muslim astronomers and engineers.

 The quadrant was invented by Muhammad ibn Mūsā al-Khwārizmī.

The illustration above was drawn by Tycho Brahe.






Sine quadrant



The sine quadrant, invented by Muhammad ibn Mūsā al-Khwārizmī in 9th century Baghdad,
was used for astronomical calculations.






Horary quadrant



The first horary quadrant for specific latitudes, was invented by Muhammad ibn Mūsā al-Khwārizmī in 9th century Baghdad, center of the development of quadrants.

It was used to determine time (especially the times of prayer) by observations of the Sun or stars.






Quadrans Novus



Quadrans Vetus was a universal horary quadrant, an ingenious mathematical device invented by
al-Khwarizmi in 9th century Baghdad and later known as the "Quadrans Vetus" (Old Quadrant) in medieval Europe from the 13th century.

It could be used for any latitude on Earth and at any time of the year to determine the time in hours from the altitude of the Sun. This was the second most widely used astronomical instrument during
the Middle Ages after the astrolabe.

One of its main purposes in the Islamic world was to determine the times of Salah.






Quadrans Vetus



The astrolabic quadrant was invented in Egypt in the 11th century or 12th century, and later known
in Europe as the "Quadrans Vetus" (New Quadrant).





 
Almucantar quadrant



The first almucantar quadrant was invented in the medieval Islamic world, and it employed the use
of trigonometry.

The term "almucantar" is itself derived from Arabic.

The Almucantar quadrant was originally modified from the astrolabe.






Sextant



The first sextant was constructed in Ray, Iran, by Abu-Mahmud al-Khujandi in 994.

It was a very large sextant that achieved a high level of accuracy for astronomical measurements, which he described his in his treatise, 'On the obliquity of the ecliptic and the latitudes of the cities'.

In the 15th century, Ulugh Beg constructed the "Fakhri Sextant", which had a radius of approximately 36 meters. Constructed in Samarkand, Uzbekistan, the arc was finely constructed with a staircase on either side to provide access for the assistants who performed the measurements.
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Bianca
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« Reply #107 on: October 13, 2008, 02:51:39 pm »



Ulugh Beg's mural sextant,

constructed in Samarkand,
Uzbekistan,

during the 15th century
« Last Edit: October 13, 2008, 02:53:34 pm by Bianca » Report Spam   Logged

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« Reply #108 on: October 13, 2008, 02:59:07 pm »










                                                           Optical instruments






Observation tube


 
The first reference to an "observation tube" is found in the work of al-Battani (Albatenius) (853-929), and the first exact description of the observation tube was given by al-Biruni (973-1048), in a section of his work that is "dedicated to verifying the presence of the new cresent on the horizon."

Though these early observation tubes did not have lenses, they "enabled an observer to focus on a part of the sky by eliminating light interference."

These observation tubes were later adopted in Latin-speaking Europe, where they influenced the development of the telescope.






Experimental device with apertures



In order to prove that "light is emitted from every point of the moon's illuminated surface," Ibn al-Haytham (Alhazen) built an

"ingenious experimental device" showing "that the intensity of the light-spot formed by the projection
of the moonlight through two small apertures onto a screen diminishes constantly as one of the apertures is gradually blocked up."






Magnifying lens



The first optical research to describe a magnifying lens used in an instrument was found in a book called the Book of Optics (1021) written by Ibn al-Haytham (Alhazen).

His descriptions helped set the parameters in Europe for the later advances in telescopic techno-
logy and his additional work in light refraction, parabolic mirrors, as well as the creation of other instruments such as the camera obscura, also helped spark the Scientific Revolution.






Telescope



Taqi al-Din invented an early telescope, as described in his Book of the Light of the Pupil of Vision
and the Light of the Truth of the Sights around 1574.

He describes it as an instrument that makes objects located far away appear closer to the observer, and that the instrument helps to see distant objects in detail by bringing them very close. He also states that he wrote another earlier treatise explaining the way this instrument is made and used, suggesting that he invented it some time before 1574.

However, it is not known whether he employed the instrument for his later astronomical observations
at the Istanbul observatory of al-Din from 1577.
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Bianca
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« Reply #109 on: October 13, 2008, 03:01:10 pm »



ALIDADE
FOR CEILING PROJECTOR
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« Reply #110 on: October 13, 2008, 03:06:48 pm »









                                                           Other instruments






Various other astrononmical instruments were also invented in the Islamic world:





Astronomical compass:

The first astronomical uses of the magnetic compass is found in a treatise on astronomical instruments written by the Yemeni sultan al-Ashraf (d. 1296) in 1282. This was the first reference to the compass in astronomical literature.



Dry compass:

In 1282, al-Ashraf also developed an improved compass for use as a "Qibla indicator" instrument in order to find the direction to Mecca. Al-Ashraf's instrument was one of the earliest dry compasses, and appears to have been invented independently of Peter Peregrinus.[182]
 


Alhidade:

The alhidade was invented in the Islamic world, while the term "alhidade" is itself derived from Arabic.



Compendium instrument:

A compendium was a multi-purpose astronomical instrument, first constructed by the Muslim astronomer Ibn al-Shatir in the 13th century.

His compendium featured an alhidade and polar sundial among other things.

Al-Wafa'i developed another compendium in the 15th century which he called the "equatorial circle", which also featured a horizontal sundial.

These compendia later became popular in Renaissance Europe.



Orthogonal and regular grids:

Islamic quadrants used for various astronomical and timekeeping purposes from the 10th century introduced orthogonal and regular grids and markings that are identical to modern graph paper.



Framed sextant:

At the Istanbul observatory of al-Din between 1577 and 1580, Taqi al-Din invented the mushabbaha
bi'l manattiq, a framed sextant with cords for the determination of the equinoxes similar to what
Tycho Brahe later used.



Qibla indicators:

In 17th century Safavid Persia, two unique brass instruments with Mecca-centred world maps en-
graved on them were produced primarily for the purpose of finding the Qibla.

These instruments were engraved with cartographic grids to make it more convenient to find the direction and distance to Mecca at the centre from anywhere on the Earth, which may be based
on cartographic grids dating back to 10th century Baghdad.

One of the two instruments, produced by Muhammad Husayn, also had a sundial and compass
attached to it.



Shadow square:

The shadow square was an instrument used to determine the linear height of an object, in con-
junction with the alidade, for angular observations.[187] It was invented by

Muhammad ibn Mūsā al-Khwārizmī in 9th century Baghdad.



http://en.wikipedia.org/wiki/Islamic_astronomy
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