According to what I can find, the astronomer Kenneth Newman arrived at Lowell Observatory shortly after the discovery of Planet X in 1930. At any rate, he begins to publish articles and to appear in Observatory photographs around 1932. It’s nice to think of Clyde having someone to work closely with — someone around his own age, I mean. And it’s a little eerie to see Newman here in this photograph, seemingly playing the part that the fictional character Alan Barber does in Percival’s Planet.
It strikes me that astronomy in that era — with its long periods of nocturnal solitude — could be awfully lonely labor; I imagine Clyde found it a relief to have somebody else around.