Algol

“I just finished Perseus. That there is Algol—the demon star. This here is pretend outer space—or fantasy outer space—so we’re not really interested in arranging the constellations the way they usually appear.”

Algol, which means “ghoul’s head,” is actually two stars that orbit each other.

Algol in the constellation Perseus, rising in the northeastern sky after nightfall near the triangular pattern formed by Capella, Mirfak, and the Pleiades cluster.

This all followed the exquisite experience of learning Algol using punch cards through the Michigan Terminal System running on Amdahl computers.

The two determined that the dimming of Algol's light occurred exactly every 2.767 days and speculated that an unseen planet was eclipsing the star.