Simplify the following text for a Grade 7 native English-speaking person.
Original: Struve wrote to his uncle Hermann Struve in Germany for assistance , without knowing that the latter had died a few months earlier , on August 12 , 1920 .
Simplified: Otto Struve ( August 12 1897 â `` April 6 1963 ) was a Russian astronomer . He was the grandson of Otto Wilhelm von Struve and the great-grandson of Friedrich Wilhelm von Struve .