About 6:15-6:20. If you're trying to make it to a 6:45 showing of CP, I did it twice (however 12/9 and 12/11, when crowds were lower). Positioned myself on the WS side of the tree (I know, can't see the characters from back there, but I think it's the best view for seeing the tree lighting). Then I walked fairly swiftly ("with purpose", but not fast) to the CP.