Very interesting, makes me want to order the spherical trigonometry book that was the source for this text. Spherical trigonometry is sometimes very non-intuiti

Very interesting, makes me want to order the spherical trigonometry book that was the source for this text. Spherical trigonometry is sometimes very non-intuitive. I recently took a few courses of university level astronomy. And as has been the tradition at least from the times of Ptolemy's Almagest in the 2nd century, we started with spherical trigonometry. When doing exercises, we'd draw triangles on oranges we got from the cafeteria. That's way better than trying to draw spheres on a flat piece of paper.