Shapley persuaded Payne to write a doctoral dissertation, and so in 1925 she became the first person to earn a Ph.D. in astronomy from Radcliffe College (now part of Harvard).[3] Her thesis was "Stellar Atmospheres, A Contribution to the Observational Study of High Temperature in the Reversing Layers of Stars".[5] Astronomers Otto Struve and Velta Zebergs called it "undoubtedly the most brilliant Ph.D. thesis ever written in astronomy".[1]