I have been on RCI's Vision (3 times), Legend, Splendour, Rhapsody an Radiance and have never seen the ceiling opened over the solarium, I have been on Princess once (Grand) and the roof was opened several times. Not that it really matters, but I wonder if anyone has ever seen the roof opened on any RCI ship?
We were on the Rhapsody in February and they opened the canopy everyday. The breeze was wonderful but the sun was much more intense with it open. They must have some sort of protective film on the glass.