Asterisms

What Exactly is an Asterism?

In modern astronomy, there are exactly 88 official constellations (defined by the International Astronomical Union in 1922). An asterism is any recognizable pattern of stars that is not one of those 88 official constellations.

• Internal Asterisms: Patterns found inside a single constellation (e.g., the Big Dipper inside Ursa Major).

• Cross-Constellation Asterisms: Patterns made by connecting bright stars from different constellations (e.g., the Summer Triangle).

Asterisms Across Cultures

Different cultures looked at the same "dots" but told very different stories based on their environment and needs.

1. The Big Dipper (Ursa Major)

This is perhaps the most "re-interpreted" group of stars in history:

• In North America: To many Indigenous groups, it was a Great Bear chased by hunters. To enslaved people in the 19th-century US, it was the "Drinking Gourd," a secret map used to find the way north to freedom.

• In the UK: It is often called "The Plough."

• In China: It was seen as the "Government Chariot" of the Emperor, or a celestial scale.

• In Ancient Egypt: It was the "Adze," a tool used by priests in the "Opening of the Mouth" ceremony to ensure an afterlife for the Pharaoh.

2. The Pleiades (The Seven Sisters)

Though it’s an open star cluster, nearly every culture has an asterism name for it:

• In Japan: It is known as Subaru (meaning "united" or "gathered together"). If you look at the car logo, you’ll see the stars!

• In Australia: Many Aboriginal groups see them as a group of young women fleeing from the hunters (the stars of Orion).

• In New Zealand: The Māori call it Matariki. Its appearance in the morning sky marks the beginning of the Māori New Year.

3. Orion’s Belt

• In Scandinavia: Before Christianity, these three stars were "Frigg’s Distaff" (a tool for spinning wool).

• In South Africa: Some Afrikaans speakers call them "Drie Konings" (The Three Kings).

• In China: Known as the "Three Stars" (Shen), representing the gods of Fortune, Prosperity, and Longevity.

Why Do We Use Them?

The purpose of an asterism is purely practical. Even professional astronomers use them as "signposts." If you can find the Summer Triangle, you can find the constellations Lyra, Cygnus, and Aquila. If you can find the "W" of Cassiopeia, you can find the Andromeda Galaxy.

They are the "shorthand" of the night sky, turning a chaotic mess of lights into a familiar map.

A Fun "Next Step"

Would you like to learn about some "telescopic asterisms"? These are tiny patterns (like the "Coathanger" or "Eddie's Coaster") that you can only see through binoculars or a small telescope. I can give you a list of coordinates for them!

Download