The largest constellation in the sky is Cygnus. Cygnus has a total of 17 stars and covers an area of 892 square degrees. It’s also known as the Northern Cross, because it looks like a cross when observed from Earth. Cygnus was first cataloged by Ptolemy, who assigned it to his list of 48 constellations that he created back in 150 AD. In contrast, Ursa Major (the Big Bear) only takes up 59 degrees on Earth’s sky and contains 9 visible stars. Another large constellation is Sagittarius which covers an area of 758 degrees and includes 18 stars with one-star being 900 times brighter than the Sun.
There are 88 internationally recognized constellations covering 1022 degrees of the night sky as defined by the International Astronomical Union (IAU). These modern-day official zodiacs were formalized in 1930, and have remained unchanged since then. The most recent constellation to be added is Mensa in July 1958. However, the ancient Greeks had about twice as many constellations. They saw patterns of stars that modern-day skywatchers don’t see.
For example, they saw a group of stars shaped like a little bear, and named it ‘Arcturus’. This is where we get the name of our brightest star. However, this pattern is not visible from the Earth. The North Star, which is the same star as our current Pole Star Polaris, has been used by navigators since it was first observed 5000 years ago. This shows that ancient people saw a pattern of stars that we don’t see today. However, ancient Greeks did not include Arcturus in their list of constellations because there was no clear pattern to the stars.
