ad-: to, at
spect: derived from Latin "specere", meaning "look"
-ion: the state of doing something
So aspection means:
One state of being looked to.
One state of being looked to means "one kind of appearance of something". All kinds of appearance will form one lifecycle of something. So aspection means one state in the lifecycle.
Evolution of usage
Moon has many states of being looked to.
Moon has many aspections.