equations and spherical coordinates. I'm usually quite good at this stuff, so I hope to be able to produce something
usefull. Maybe XD.
My big question is the spacing between the great circle and the ruin position. As I understand it, the ruin lays on a parallel circle (i.e. not a great one)
so that the moon will trace an arc < 180°. If you could explain to me the separation between the great circle and the ruin "smaller circle" I would
be glad. (and be able to compute stuff).
I will start to draw it. Maybe something will clear up.