Dating of a Latin astrolabe

Abstract

We have determined the most probable date for the catalog of 34 stars that was used in the construction of a Latin astrolabe originally owned by the Dominican preacher friars and presently at Mus\'ee des Arts pr\'ecieux Paul-Dupuy (Toulouse, France). To this end we digitized a photograph of the rete and the rule of the astrolabe, computed the equatorial coordinates of the ends of the 34 star pointers of the rete, and produced a list of 113 reference stars taken from several lists of stars on astrolabes. We then compared the coordinates of the ends of the pointers and those of the reference stars for dates between 1400 and 1700. The most probable date for this astrolabe is 1550.