10 Facts About Ejnar Hertzsprung

Ejnar Hertzsprung is best remembered for his role in developing the Hertzsprung-Russell diagram of stars.

Ejnar Hertzsprung studied chemical engineering at Copenhagen Polytechnic Institute, graduating in 1898.

Ejnar Hertzsprung's father was an amateur astronomer, which led to Ejnar's interest in the subject.

Ejnar Hertzsprung began making astronomical observations in Frederiksberg in 1902, and within a few years had noticed that stars with similar spectral type could have widely different absolute magnitudes.

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

Ejnar Hertzsprung used this relationship to estimate the distance to the Small Magellanic Cloud.

From 1919 to 1946, Ejnar Hertzsprung worked at Leiden Observatory in the Netherlands, from 1937 as director.

Ejnar Hertzsprung used the earlier classification system developed by Antonia Maury in his work.

Ejnar Hertzsprung discovered two asteroids, one of which is 1627 Ivar, an Amor asteroid.

Ejnar Hertzsprung's wife Henrietta was a daughter of the Dutch astronomer Jacobus Kapteyn.