﻿ Uses of the Astrolabe  Uses of the Astrolabe  In the 10th
century, Abd al-Rahmân b. Umar al-Sufī (d. A.H. 376/A.D. 986-7)
wrote a detailed treatise on the astrolabe consisting of 386
chapters in which he described 1000 uses for the astrolabe. al-
Sufī perhaps overstated the flexibility of the astrolabe, but
astrolabes can be used to solve many astronomical problems that
would otherwise require rather sophisticated mathematics. All of
the everyday uses of the astrolabe are not known, but they were
certainly used to tell time during the day or night, to find the
time of sunrise and sunset and, thus, the length of the day, to
locate celestial objects in the sky, as a handy reference of
celestial positions and, as astrology was a deeply embedded
element of the cultures that used astrolabes, to determine
aspects of horoscopes. Islamic prayer times are astronomically
determined, and the astrolabe could be used to determine the
required times. Modern astrolabes, such as The Personal
Astrolabe, can be used to solve