After Otto obtained his Ph.D. in physics from the University of Helsinki, he studied at the Pulkovo Observatory with the German astronomer Herman Romberg, whose daughter, Margarete Henriette Louise Romberg, he married in 1892. Otto and Margarete then settled in Joensuu, where Otto taught physics, and there their four children were born: Frithiof (born 1894; also a mathematician), Rolf (born 1895), Anna (born 1896) and Erik (born 1901).
after otto obtained his phd in physics from the university of helsinki he studied at the pulkovo observatory with the german astronomer herman romberg whose daughter margarete henriette louise romberg he married in 1892 otto and margarete then settled in joensuu where otto taught physics and there their four children were born frithiof (born 1894; also a mathematician) rolf (born 1895) anna (born 1896) and erik (born 1901)