I found this about refraction (on Wikipedia) --
It would be interesting to apply this formula and then look at the pictures in the video again.
I just took the first one here --
Distance = 443 km
Viewer Height = 9,252 feet
Target Mountain Height = 12,740
Hidden = 16,534
so, if I take 443 / 1500, I get .295
Then I multiply the mountain height by 1.295 and get 16,498 ... still a few feet bellow what should be hidden.
Unless I'm misunderstanding how this works.