Dear Safarists,
Ibn Khaldun said in Al-Muqadima:
نقول إن قطبي الفلك الجنوبي و الشمالي إذا كانا على الأفق فهنالك دائرة عظيمة تقسم الفلك بنصفين هي أعظم الدوائر المارة من المشرق إلى المغرب و تسمى دائرة معدل النهار و قد تبين في موضعه من الهيئة أن الفلك الأعلى متحرك من المشرق إلى المغرب حركة يومية يحرك بها سائر الأفلاك في جوفه قهراً و هذه الحركة محسوسة و كذلك تبين أن للكواكب في أفلاكها حركة مخالفة لهذه الحركة و هي من المغرب إلى المشرق و تختلف آمادها باختلاف حركة الكواكب في السرعة و البطء و ممرات هذه الكواكب في أفلاكها توازيها كلها دائرة عظيمة من الفلك الأعلى تقسمه بنصفين و هي دائرة فلك البروج منقسمة باثني عشر برجاً و هي على ما تبين في موضعه مقاطعة لدائرة معدل النهار على نقطتين متقابلتين من البروج هما أول الحمل و أول الميزان فتقسمهما دائرة معدل النهار بنصفين نصف مائل عن معدل النهار إلى الشمال و هو من أول الحمل إلى آخر السنبلة و نصف مائل عنه إلى الجنوب و هو من أول الميزان إلى آخر الحوت و إذا وقع القطبان
على الأفق في جميع نواحي الأرض كان على سطح الأرض خط واحد يسامت دائرة معدل النهار يمر من المغرب إلى المشرق و يسمى خط الاستواء
For those who studied the previous two emails of astronomy:
First: http://groups.yahoo.com/group/SaharaSafaris/message/8405
then: http://groups.yahoo.com/group/SaharaSafaris/message/8412
Being able to understand Ibn Khaldun is your REWARD (a puzzle?! :) the astronogmical introductions and emails should enable you to understand some ancient description of the Celestial Sphere in Ibn Khaldoun's words himself!! The GREAT "Tunisian" scholar who has impressed all Western historians and sociologists till today.
He seemed like he understood very well all the geometrical characteristics of the model and was trying to simplify, but how far can anybody simplify? It won't be easy the first round of trying to understand its astronomy, but soon, you'll be able to 'decipher' books by Avicenna (Ibn Sina) and Averroes (Ibn Rushd), etc. fima yata3allaq belkawn wa alfalak faqat taba3an wa laysa koll shay2en men 3elmehem alghazir :)
This is obviously for native Arabic speakers or those who are highly trained in Arabic language only.
First please PRINT Ibn Khaldoun's words (you'll use this coz you might like to mark the words. We'll try to understand them word by word fii daw2 ma3loomatena al-falakia alati sabaq shar7oha :) If you cannot read them go to the browser menu: View | Encoding | Arabic (Windows)
Ok!
Now let's define some words to clarify the complex ideas that Ibn Khaldoun was trying to explain:
Qutb (plural: Al-Aqtaab) = Pole of either Earth or Celestial Spheres
Da2era 3azimah = Great Circle (

Al-Falak (Al-A3la) = Celestial Sphere or Celestial Dome (half sphere) as seen from Earth
Al-Aflaak = Celestial (Bodies/Constellations/Regions not sure?)
Al-Boroug (sgl: Borg) = Constellations (specially Zodiacal)
Mamar = Path (eg, the 'path' of the Sun is "Ecliptic" Circle)
Ofoq =
Al-Mashreq, Al-Magherb = East and West on BOTH Celestial and Earth spheres
Da2erat Mu3addel Al-Nahar =
Da2erat Falak Al-Boroug =

Awal Al-7amal = First of Aries (Vernal Equinox). Do you know that the Ecliptic actually moved from time of Ibn Khaldoun when the intersection of the Ecliptic and C.Equator (Vernal Equinox) were at the Aries??? It's now at Pisces! Even as we speak today the Vernal Equinox located in the far edge of Pisces is called 'First of Aries' in Western Astronomy!
Awal Al-Mizaan = First of Libra (Autumnal Equinox). Same as Awal Al-7amal.
Samt (verb: yusaamet) = Corresponding point in the other sphere (Earth or Celestial Sphere). An observer-person has his 'Samt' point in the Celestial Sphere at the Observer's Zenith. The Sun 'TUSAAMET' a person when it's at the Zenith of this person. Celestial Equator 'YUSAAMET' Earth's Equator. Geometrically, a point is (MUTASAAMETAH) with a star when an imaginary line that passes them could pass too through the Earth's centre. For lines, only Great Circles can be (MUTASAAMETEEN) and are having a plane passing through them that could pass through Earth's centre too. In layman's terms (compromising accuracy indeed), a Celestial point or line are (mutasaameteen) with others on Earth when they're exactly 'above' them. This is wider definition of the simple 'Zenith' word. 'Zenith' is usually the translation of "Noqtat Al-Samt".
Aaaaaall questions/comments are welcome on SSC. Ibn Khaldun deserves all that and more. :)
I might sound like a crazy dreamer but.. only crazy dreamers can come up with ideas like the Egyptian pyramids!
-------
Yahoo! for Good
Click here to donate to the Hurricane Katrina relief effort.