First constructed between first and second century B.C., AstroLabes have played a critical role in the development of astronomical theory, mathematics and navigation. This ancient astronomical instrument was used to locate and predict the positions of the sun, moon, planets and stars. It also was used to determine local time based on longitude, assist in astronomical studies, navigation, and construct horoscopes. Now own your own AstroLabe as incorporated into this beautiful timepiece. The water-resistant watch features dual time zone, four hand movement with 24 hand & index.A blue silicone rubber strap is accompanied by a 316L steel buckle in a case made from a combination of polished and brushed surfaces.