They built a shell around the original building to add to the overall floor space. The original exterior of the building is "preserved" inside the new exterior. There's a food court now on the north side which of course gives panoramic views of the city skyline. The lower level is completely remodeled, and if you remember the old optical shop in the lower level (where I was fortunate enough to finish off an 8" mirror with the help of the optical shop director at the time) is gone, replaced by new exhibits.
But the main interior sky theater is the big heart break for me. They replaced the original first class Zeiss projector with so-called modern digital special effect equipment which renders the sky poorly in my opinion. You can watch a bright star, for example, change in appearance as the star is "handed off" to a different sub-projector (so the entire sky is rendered by multiple projectors) as the sky is moved. Special effects are korny at best. But the per-show profit is higher since by removing the original Zeiss projector they got to put in more seats in the theater which of course probably was the motivation to mothball the Zeiss projector.
In all, very sad.
What a shame. I hope to visit it again someday, but I just might skip the sky show.