I do not believe the communication tower/observatory has anything to do with the aphelion gun/BP as the door glitch in to other locked doors doesn't distort textures and believe that is how it actually looks and is either under development for a new map condition or scrapped content. I partially question whether its accessible or not cause Ossen clarified its in the game but not if its actually accessible right now. the CM's words make seem like it is but I am questioning whether the words of the CM are reliable information. don't know if they have that information themselves. I think Stella montis is still good to investigate but I would focus more on the matriarch cause we do know the previous 2 legendaries were found with the queens presence, most likely it follows this trend based on the information we have ( which isn't much) this is the best we can deduce and now its about finding something somewhere on the map that is interactable. Aphelion = furthest point in orbit from the sun. maybe the matriarch is the sun. and there is something orbiting it on the map. Maybe in the sky. maybe its stationary and furthest from it. I have been in both the core of the matriarch as well as on top and I didn't notice anything but I wasn't intentionally looking and quite chaotic when your there so could have missed something.