Astrolabe Catalogue

The design of this astrolabe reflects the importance of astrology for makers and users of such instruments. On the single plate, engraved for 49° (Paris), the maker, Pierre Sevin, has engraved the twelve lines representing the horoscopic house divisions. The rete, in turn, has been reduced to simply an ecliptic band and five stars, making it easier to read the positions of the zodiac that correspond to the boundaries between the horoscopic house.

The astrologer would set the alidade to a particular time, for example 9:00 am, according to the equal hour divisions around the limb. Then he would rotate the rete until the sun's position in the zodiac was directly under the front edge of the limb. At that point, the astrologer would read the house divisions directly from the ecliptic where the lines crossed under the ecliptic band.

It was not uncommon to find the horoscopic houses engraved on astrolabe plates. What sets this instrument apart is the correspondingly simple rete design and the absence of other plates.

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