hertzsprung

noun

1. Ejnar (ˈəɪnar). 1873–1967, Danish astronomer: he discovered the existence of giant and dwarf stars, originating one form of the Hertzsprung-Russell diagram

1. Danish astronomer who specialized in photographing the stars and introduced the concept of absolute magnitude. Hertzsprung also demonstrated the relationship between the surface temperature of stars and their absolute magnitude, but his work was ignored until Henry Russell independently developed a similar correlation, which is now named after both of them.