In 1930 he joined the Solar Research Station run by the National Geographic Society and the Smithsonian Institution at Brukkaros, the caldera of an extinct volcano in South West Africa (Namibia).

American researcher William H. Hoover and his colleague Frederick Atwood Greeley, ran an observatory on the mountain from 1926 to December 1931, collecting solar radiation data so as to find a correlation with the earth's weather.

A solar telescope or coelostat at the mouth of the tunnel passed sunlight to a spectrograph, an Ångström compensation pyrheliometer and a bolometer further in.

[1] During this period he took sabbatical leave and studied under Sir Arthur Eddington at Cambridge, Professor Hans Ludendorff of the Astrophysical Observatory at Potsdam and Ejnar Hertzsprung at Leiden.

His gift of being able to articulate difficult concepts in the fields of astronomy and applied mathematics, made him a popular tutor and inspired thousands of students who sat through his exceptionally lucid lectures.