Lenses and Waves

1653 - TRACTATUS 51
expect that theory could be useful. The discovery that a sphere is an
aplanatic surface in some cases had given the initial impulse to his interest in
dioptrics. In his letter to Van Schooten, he expressed the expectation that
this theoretical insight would contribute to the improvement of the
telescope. From the very start, Huygens saw a connection between the
theory of dioptrics and the practice of telescope making. In the next chapter
we shall see what he would make of it.