Astrolabes were continually improved upon and enjoyed widespread popularity during the Renaissance. A vast range of other computational and measuring instruments (based principally on the writings of Ptolemy), such as quadrants and various devices for measuring the time of day and night, were produced. These beautiful and ingenious objects with their fine engravings, bear eloquent witness to the close link between technical skills, mathematical expertise and the search for elegance and proportion that characterized the production of astronomical instruments in the 15th and 16th centuries.