#hyperray

That's a good question! I haven't done a lot of thinking on the state of their astonomy, but I know it lags behind their biology tech a fair bit.

Going up and perching on the "sky" (ceiling of the bladder) is a pretty big thing for flying insects, though, especially ones that just became adults (got their wings). With their nearsightedness, they can't really see the stars with the naked eye. And there's no actual moon, either. However, each bladder has a point that focuses starlight to simulate a moon, and there are smaller points of focus that can be used as stargazing portals once you're up there.

They do have "space travel" to a degree--a space rail system for traveling between the bladders. Macrovolutes can even survive in the vacuum of space for (very) brief periods!

Attempts have also been made to visit Angion before, so they're very aware what a planet is.

Oops my hand slipped-

Here’s a drawing of Drossel from the anime shorts Fireball, requested by the lovely @hyperray