It will be along time before any “high school” students take up the formal study of Classical Astronomy in Ptolemy’s Almagest. In fact, few may ever do so. It’s very difficult and will likely require the help of a tutor.
As an alternative, I recommend that students study Aristotle’s Physics and then his work On the Heavens. This work came before Ptolemy’s Almagest in history and is easier for students to get started with. It requires the knowledge of Classical Geometry because in it, Aristotle uses Geometry to prove many of his teachings on the heavens.
I’m always available for help with these lessons for any motivated students.
William C. Michael, Headmaster
Classical Liberal Arts Academy