This is before he was my dad.
He had a job with the Smithsonian Astrophysical Observatory after college where he, among other things, travelled around the world with a precise clock (which he helped design) to set the times in their various satellite observatories before there was a way to easily do it via other mechanisms. He has some pictures from when he was there in his own photostream.
This is a silly promo shot. Dad with "atomic clock", stewardess sets watch. Probably in 1966, so my father was 27 years old.