The images on astrolabes, "star takers," indicate a focus in astronomy/astrology because of the presence of the symbols of the zodiac and star charts which would be used for casting horoscopes for royal courts. Because of the expense in making them, they were often found in in the residences of the wealthy where they could also be displayed as works of art. European astrolabes would often have a calendar of saints' days. Other astrolabes have Hebrew script, and Islamic astrolabes could be used to calculate the times for prayer and to locate the direction of Mecca. They truly were cross-cultural and scientific-religious devices. This ancient technological device was found in many different cultures which shows how scientific knowledge spread throughout the Mediterranean world and surrounding areas just as technological/scientific knowledge spreads on a global basis in the modern world. Students would see the astrolabe as an earlier version of today's portable technology such as tablets, laptops, smart watches and phones which can be found all over the globe.