Pearl Harbor, on a clock nobody uses now

The first bombs fell at 7:48 in the morning, on a Hawaii that was running half an hour off the rest of the world.

The territory kept UTC minus ten and a half hours until 1947, so Honolulu clocks were 30 minutes behind the modern zone. Get that wrong and every reconstruction of the morning is half an hour out — which is the sort of detail that decides whether a computed sky matches an eyewitness account.