On the large scale map I took the clue quite literally and used the highest point in France to align my flight. The relative distances have already been worked out on the clue page and fit well on my final map. For verification that this is the right track I considered the alternative French definitions for arrow and the need for an immovable, definite target and enjoyed reviewing the church spire within 1000m of where my arrow fell.
Apollo’s Arrow is also the title of a non-fiction book.
The title of the book is a reference to a mythical arrow that once belonged to the god Apollo. According to legend, the arrow was gifted by a priest to Pythagoras, allowing him to dart through space and time.
“he will count 1969,697 measures towards the zenith.” is a distance (Space)
“In a 46,241,860th fraction of sidereal day,” is a duration (Time)
Pythagoras is used to calculate the length of the 3rd side of a right triangle, when given the length of the other 2 sides.