👉 "Apex" is a term used in astronomy to describe a point where an object's motion or orbit is at its highest point. In this context, "iapetus" refers to the point in the sky where Jupiter's moon Io lies at its highest point. This astronomical event occurs when Io passes directly above Jupiter, marking the apex of Jupiter's orbit around the Sun. Io is also known as Io 1779 or Io 1803, depending on its position