Georg Heinrich Thiessen

Georg Heinrich Thiessen (19 January 1914 – 3 July 1961) was a German astronomer.

In January 1945 he was transferred to the observatory in Hamburg-Bergedorf, where he was employed as assistant and later as 'Observator' from 1946 to 1953.

On 3 of July 1961 he was killed in a frontal collision with a tram, his wife was seriously injured in this accident.

He discovered that the granulation, filling the entire solar surface outside sunspots, cannot be observed in the umbra.

They are difficult to observe due to their small size and because of the high brightness contrast between the sunspot umbra and the surrounding photosphere.