In 1913 he determined the distances to several Cepheid variable stars by statistical parallax .
Was thus able to calibrate the relationship discovered by Henrietta Leavitt between Cepheid period and luminosity .
In 1913 he determined the distances to several Cepheid variable stars by statistical parallax , and was thus able to calibrate the relationship discovered by Henrietta Leavitt between Cepheid period and luminosity .