Astronomy Cast: Constellations

This Astronomy Cast discussed the 88 constellations identified so far. In astronomy, a constellation is an internationally defined area of the celestial sphere. It is also known as a pattern formed by prominent stars within apparent close proximity to one another. A simple definition is a group of celestial bodies, usually stars, which form a pattern in the sky. A star pattern that is not officially classed as a constellation is an asterism. These are all things were are learning in our Astronomy class so it was interesting seeing how much I was familiar with. One of the most commonly known asterisms is the Big Dipper, which is part of the constellation Ursa Major, or Big Bear. Another famous constellation is Orion, the hunter. Most people can point out Orion's belt in the sky even if they aren't aware it's a constellation. The two major first magnitude stars of Orion are Rigel and Betelgeuse. The constellations are divided into four seasons -- Winter, Summer, Spring and Autumn because certain constellations are only visible in the sky certain times of the year depending on the Earth's tilt on its axis and its location in orbit. However, there are some constellations which are circumpolar, meaning they are by the North Pole so are visible all year round. Some of these circumpolar constellations include Cepheus -- The King, Cassiopeia -- The Queen and Perseus -- The Hero. Also, all of the star signs we are familiar with in astrology (eg. Aquarius, Sagittarius) are all constellations under the category "zodiacal." It's so interesting to see how many modern words and names are derived from asterisms, stars, or constellations. One that stuck out to me the most were that Sirius and Bellatrix are both stars and are both characters in the Harry Potter series.