星云 so elegantly describes what a nebula is! I love it.

天文学 is fascinating, isn't it? Apparently the historical Chinese constellations are quite different from the Greek ones, although there is some overlap too e.g. Big Dipper/Orion/Pleiades.

Following the 天文学 theme, 动如参商 - 'as Orion and Antares', eternal separation.