adjective
lunar
LOO-ner/ˈluːnər/
Relating to the moon.
The lunar surface shows craters and dark plains.

Etymology
The pieces give the literal meaning “relating to the moon.” English also used the word for a crescent shape, connecting the moon's visible outline with things that resemble it.
In context
the moon takes on a coppery color when it's not so clear the result is a dark crimson or even brownish lunar eclipse