The Emirate of Sharjah is the third largest emirate in the United Arab Emirates, and is the only one to have land on both the Persian Gulf and the Gulf of Oman. This stamp commemorates the achievements of Arab Astronomers whose achievements include measuring the earth’s circumference, the determination of the solar year, advances in optics, lenses and mirrors, the position of planets at any given time and the prediction of solar and lunar eclipses.