We went to the Planetarium to catch a show on a whim on a Wednesday afternoon after seeing the Museum of Illusions (which was awesome) it was $24 for 2 adults & a child.
My daughter and I lay on one of the big poufs on the floor and my husband sat in a seat near us.
The preshow was awesome; it was just soft music and pictures of space. My daughter loves space. She's almost 8.
The show started (The Magic Treehouse) and it was a bit silly. Like something you'd take a first graders to see on a field trip. But, I'm not a spoil sport so I adjusted my expectations and snuggled into my pouf. Honestly, the most egregiously unrealistic thing to me was the idea of Morgan Le Fey & Merlin being friends and either of them interacting with children in a positive manner. But I'm kind of a giant nerd. Neither of them ended up actually being in the show anyway.
I'm almost positive I would have gotten motion sickness if I hadn't been laying down so... Yay for poufs!
The best part was the twist ending which I legitimately didn't see coming.
But as for the planetarium itself: We were comfortable, it wasn't too crowded, tickets were reasonable, it was a smooth and enjoyable experience.