What is a constellation?

People try to find a pattern in everything they see in nature. The ancient Greeks also did so when they observed the stars. They found that eight stars together looked like a whale, while some other stars seemed to resemble a lion or a bear. They put together these groups of stars as pictures, many of which we can hardly track these days. The reason is that the stars have changed positions in the 3000 years that followed after the Greeks first observed the constellations. However, the following constellations can be seen very clearly in the northern hemisphere: Pisces, Aries, Taurus, Cassiopeia, Perseus, Auriga, Orion, Gemini, Lynx, Cancer, Little Dipper, Draco, Herdsman, Hercules, and Ophiuchus.