Form the article I posted here:

Most of what is known about so-called noctilucent clouds — thin, beautiful wisps that hover at the edge of the Earth’s atmosphere — comes from 30 years of astronauts sketching and trying to photograph them in their spare time.

noctilucent - shining or glowing by night (Example: The noctilucent eyes of a cat)

"My Dear, you look positively noctilucent tonight."

I suppose boy fireflies say that to girl fireflies, huh Shu?