0 the scientific study of the physical features of the moon: --
Today, selenography is considered to be a subdiscipline of selenology, which itself is most often referred to as just lunar science.
Heliology and selenology were subjects which he studied with special interest, and on which he speculated with ingenuity as well as learning.
The expeditions of astronauts greatly facilitated selenology.
The study of the geology of the Moon falls under the more general field of lunar science, i.e., selenology.