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The night sky is filled with stars. Some of them are part of constellations, named after animals or figures in Greek mythology, that were designated to make it easier for people to locate them in celestial sphere. Constellations were excellent guides for travelers and navigators, and served as a tool for astrologers to predict one’s future. Constellations originate from Old Babylonian astronomy, which was practiced by nomadic tribes thousands of years ago. Series of ancient tablets found in the region show engravings of some 20 constellations, including 12 along the ecliptic - the apparent paths of the Sun and the planets across the celestial sphere - such as Aries, Taurus, Gemini, and Cancer. The ancient nomadic tribes had to continually move from one place to another to find pastures for their livestock, and the stars and celestial phenomena must have been essential indicators of time and change of seasons for them. Ancient Egyptian merchants who traded across the Mediterranean Sea also designated constellations for use as navigational guides. These ancient astronomical systems were adopted later by the Greeks, and the constellations were named after gods, heroes, and beasts of Greek mythology. Since then, many more constellations have been named by astrologers and scientists. People in each region of the world gave them different names, identified them in their own unique way, and divided the celestial sphere as they saw fit. This caused great confusion worldwide. Then, in 1930, the International Astronomical Union (IAU) divided the celestial sphere into 88 constellations and established them as the official modern constellations. They include 12 constellations along the ecliptic, 28 in the northern sky, and 48 in the southern sky. Though the constellations seem to be static in the sky, they actually move slowly across it due to the Earth’s rotation and its revolution around the sun. They move approximately 15°each hour from east to west and about 1°to the west each day relative to the exact time of the previous day. This is the very reason why we see different constellations at different times of year. The“Stories of the Constellations”stamps feature an overview of the twelve constellations associated with Greek mythology as well as the four constellations that each represent a season. The stamp sheet includes brief stories of the featured constellations and their shapes to help philatelists enjoy the night sky even more.