In 1920, he moved to Berlin. During the first school years, von Braun attended a French secondary school in Berlin. At the age of 13, he got a telescope. This gift raised his interest in astronomy. Because of bad marks, von Braun had to attend a boarding school near Weimar, in 1925. He bought with his extra money the book "Die Rakete zu den Planetenräumen" ("English: The Rocket into Interplanetary Space") by Hermann Oberth, which is the basis of the modern rocket research. In 1928, he attended the boarding school called Hermann-Lietz-Internat on the German island Spiekeroog. In 1930, he passed his final exams.