Astrolabe Catalogue

This early Persian astrolabe, the oldest dated astrolabe in the collection, reflects conventions that were common to Greek instruments. As with Greek instruments, most of the plates lack azimuth lines. More interesting, however, is the set of planetary symbols used in the tables of astrological terms and faces found on the back of the instrument.

The tables of terms and faces on this instrument are distributed in an unusual manner, stretching across three quarters of the back of the instrument, in contrast to the more typical semicircle tables found on most Islamic instruments. Another unusual feature is that the maker used symbols to denote the planets rather than the last letter of the name of the planet. The most striking feature of this table, however, is the symbols themselves, which derive from the Greek symbols for the planets.

In the picture, the outer ring of text shows the last third of the zodiac — going anticlockwise from Sagittarius (القوس) to Pisces (الحوت). The next ring are the symbols for the terms — Jupiter looks like a horizontal Z; next comes Venus, Mercury, Saturn and Mars. The next ring gives the number of degrees for each term. Finally, the inner ring shows the symbols for the astrological faces: Mercury, the moon, Saturn, Jupiter, Mars, the sun, Venus. These symbols can be compared to other similar tables on astrolabes linked below.

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