Hans Oswald Rosenberg

He worked in the University of Tübingen before losing his job in Nazi Germany for having Jewish descent.

He studied correlations between spectra and magnitude and produced a precursor of the Hertzsprung-Russell Diagram in 1910 using stars at similar distances within the Pleiades cluster.

[1] Rosenberg was born in Berlin to banker Hermann and wife Else née Dohm.

With the rise of Nazi power, he was initially allowed to teach even though he had Jewish ancestry (the family had converted to Protestants[2]), since he had served in World War I; however, this changed in 1933 when he was forced to take leave of absence.

In 1934 he was allowed to travel to the United States where he began to teach at the University of Chicago and work at the Yerkes Observatory with Otto Struve.