Page 72 - Arabian Studies (V)

62 Arabian Studies V
confronting the medieval astronomer; tables for timekeeping by the
sun and stars and for regulating the times of prayer, which in Islam
are astronomically defined; treatises on astrology; and treatises on
a wide range of other related topics. Of this literature the zij and
other tables for specific purposes such as timekeeping or construc­
ting instruments are the most important category for the historian
of science.3
There has been an active tradition in mathematical astronomy in
the Yemen from the tenth century down to the present.4 This is
reflected in about one hundred medieval astronomical manuscripts
of Yemeni provenance that have been located in the past few years
in various libraries in Europe and the Near East, and furthermore
the scope of the surviving astronomical writings suggests that other
works were compiled that are now no longer extant. It must be
stressed at the outset that we have very little evidence of original
observations carried out in the Yemen, and that the Yemeni astro­
nomical works are of interest to the history of science mainly
because they incorporate earlier ‘Abbasid or Fatimid material no
longer extant in its original form. Also the Yemeni tradition of
mathematical astronomy is distinct from the tradition of folk
astronomy attested in the simple Yemeni almanacs on which there
is already some published material.5 This folk astronomy relates the
seasons, whose passage is determined by the progress of the sun
along the ecliptic, to agricultural and meteorological patterns.
The earliest Yemeni astronomer on whom we have any reliable
information is the celebrated late tenth century geographer Al-
Hamdani. He compiled a Zij which was used in the Yemen at least
until the thirteenth century. Unfortunately this is no longer extant,
but we know from a surviving fragment of al-Hamdanl’s treatise
on mathematical astrology that he was familiar with the earlier
astronomical handbooks (zij) of the astronomers of ‘Abbasid Iraq.
Most of these are likewise lost, and it is a complicated task for the
historian of Islamic science to gather information on these works
from such valuable sources as al-Hamdam’s chapter in his treatise
1 on astrology dealing specifically with the different opinions of his
predecessors.
Under the Rasulid Sultans there was considerable activity in
astronomy in the Yemen, some of which was conducted by the
Sultans themselves. The two astronomers al-Faris! and al-Kawashi
were apparently sponsored by the Sultan al-Muzaffar. Al-FarisI
| prepared a Zij containing tables for the Yemen, based on a twelfth
century Iraqi zij, and al-Kawashi prepared a zij with tables specifi­
cally for Aden and Ta‘izz, recording observations which he had
made himself in Egypt, and incorporating material from earlier

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