Astrolabes in Islam

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Astrolabes in Islam

• A model of the universe you can hold in your
  hand.
• By Dr. Harold Williams
• http//montgomerycollege.edu/Departments/planet

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Internet Astrolabe resources

• http//astrolabes.org Janus, Jim Morrison, best
  general source of astrolabe information on the
  net. The electric astrolabe a free download only
  works on Wintel machines. The best laminated in
  plastic plainspheric astrolabe.
• http//www.mathsyear2000.org/museum/floor2/gallery
  4/indastro/index.html Keith Powell's Java
  astrolabe.

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Recently made Islamic Astrolabe

• Dr. Hasan Bilani, University of Aleppo, Syria
  November 2000
• It is not a reproduction of a specific instrument
  but is in the style of a typical, high quality
  Islamic astrolabe.
• It was designed using AutoCAD and was engraved by
  chemical milling.
• It required about two months to manufacture. It
  is made of brass and is about eight inches in
  diameter and 5.5 mm thick and weighs 900 gm.
  There are 23 stars precessed to the current
  epoch. There are six plates provided but only two
  can but only two can be held in the mater at a
  time. The quote from the Koran on the throne
  (kursi) is "and by the stars (men) guide
  themselves".

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Rete
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Matter
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Climate or tympanum, 1
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Climate or tympanum, 2
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Climate or tympanum, 3
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Horizons Plate for casting Horoscopes
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Part of the Astrolabe

• Rete, net in Latin, the star map, off axis circle
  the ecliptic (the zodiacal signs)
• Plates (climate or tympanum), latitude specific,
  horizon coordinate system, altitude and azimuth

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Janus astrolabe rete
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Stereographic Projection of Rete

• For a rete to represent the Northern hemisphere

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North pole, equator, and tropics projection
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Ecliptic projection
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Rete for 2800BCE
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Rete for 500BCE
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Rete for 140
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Rete for 2000
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Rete for 13400
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Plate (climate or tympanium)

• Altitudes or almucanters
• Twilight Arcs, -6º Civil, -12º Nautical, -18º
  Astronomical
• Azimuths
• North 0º 360º
• East 90º
• South 180º
• West 270º

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Altitude Projections
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Lines of equal Azimuth Projection
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Hour angle Projections
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Complete Climate Projection
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Climate for 25 degrees
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Climate for 30 degrees
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Climate for 35 degrees
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Climate for 40 degrees
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Climate for 45 degrees
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Climate for 50 degrees
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Climate for 55 degrees
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Climate for 60 degrees
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Plate for 0 and 90 degrees
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Plate for ecliptic transformation
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Plate for all horizons in 5 degree increments
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Back of astrolabe

• Highly variable
• But most had calendar and zodiac
• angle measuring protractor
• Notice perihelion and aphelion and center of
  calendar zodiac

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Janus astrolabe the college edition
Set for July 25 at 10PM at Takoma Park, Latitude
3858.
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Astrolabe styles in Islam

• Persia http//en.wikipedia.org/wiki/Persia Iran
• Mashriq http//en.wikipedia.org/wiki/Mashriq
  Arabic Middle East
• Maghrib http//en.wikipedia.org/wiki/Maghreb
  North Africa
• Andalusia http//en.wikipedia.org/wiki/Andalusia
  Moorish Spain

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    Astrolabes in Islam references

• Islamic astronomy http//en.wikipedia.org/wiki/Isl
  amic_astronomy
• Muslim astronomers http//en.wikipedia.org/wiki/Mu
  slim_astronomers

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Some Islamic Astronomers

• Abd Al-Rahman Al Sufi (December 7, 903 May 25,
  986) http//en.wikipedia.org/wiki/27Abd_Al-Rahman
  _Al_Sufi Amazing treatise of 386 chapters
  presenting 1000 uses of the astrolabe

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Astrolabes reaching the West

• Gerbert of Aurillac, Gerbert d'Aurillac, Pope
  Silvester II, (ca. 950 May 12, 1003)
  http//en.wikipedia.org/wiki/Gerbert_of_Aurillac