While browsing Von Braun's papers online, I found his planner from 1969. It's a modified phone book as you can see from the letter ordered pages, which is interesting in itself considering that he was at the helm of the Apollo program and he could probably afford something more professional looking. My weird question - probably for the wiser (aka older ) people here - is about the weird line at the center of each page. Some parts are red, some are not, it's handmade, and central. What is the meaning of that visible red line? Is it an older method to checkmark things, or to signal a follow up item?