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Pi-Lover’s Delight

January 31, 2022

Skywatchers came up with some great names for the stars that outline the body and belt of Orion the hunter: Rigel, Betelgeuse, Bellatrix, Mintaka, and others. When it came to his shield, though, the imagination just pooped out. Six stars in a row are called Pi Orionis. The only thing that sets them apart is that they’re numbered from top to bottom.

Orion is in the southeast at nightfall. Look for his three-star belt inside a box of four bright stars. If you follow the belt to the upper right, the first decently bright star is Pi-3. The stars that share the name line up to its upper left and lower right.

Orion’s more lyrical names date back thousands of years. They came from Greek and Roman mythology, and many were translated to Arabic.

Those proper names were given only to bright stars. In the early 1600s, though, Johann Bayer assigned names to more than 1500 stars. Other astronomers added to the list.

Bayer was looking for a simple way to catalog the stars. So he designated each star with a letter of the Greek alphabet followed by the name of its constellation. In a few cases, two stars appeared so close together that they got the same letter, with each one getting its own number. Pi Orionis, however, is an exception. The stars are spread as wide as your fist held at arm’s length, so there’s no way to get them confused. Even so, they share a name — Pi Orionis: the stars of Orion’s shield.

Script by Damond Benningfield


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