A bunch of people in-game seem to think its a temporary event thing, but I didn't see any mention of that in the 5.5 patch notes... however the very nature of the Firmament has been that it is something that always evolves (things like Concerted Works are now gone, rankings are gone), so I am wondering if the Skyrise Celebration will be similar.

They say that the Firmament will periodically celebrate its reconstruction--does that refer to the 24-48 cooldown between the start of the fêtes, or does that mean that from patch to patch we may or may not always have access to fêtes.