Interesting Trifold Layout and fun premise! As a whole I really like the adventure location, each area is interesting and has some fun things to interact with. Very thematic and evocative, while immanently usable at the table. I feel like I'd struggle to drop this one in just anywhere: it's a surprisingly high-stakes adventure, but it also doesn't make clear why exactly the cultists want to destroy the sun. From a player standpoint, it feels like there is less room to go off-track (assuming the cultists succeed, that destroying the sun would be apocalyptic) or the party doesn't have a choice but to stop the cultists if they want to actually live their lives. There doesn't seem to be much incentive to join them. I feel I'd have to lampshade/foreshadow this adventure well in advance for it to mesh properly into a campaign. That is just a personal take though, I think if the adventure was longer there would be more space to flesh out the cult, or a second faction to add a bit more dynamism. the actual location itself is very cool and would definitely be fun to run in a one-shot!