Johan Oskar Backlund was a Swedish-Russian astronomer. His name is sometimes given as Jöns Oskar Backlund, however even contemporary Swedish sources give "Johan". In Russia, where he spent his entire career, he is known as Oskar Andreevich... Wikipedia
Born: April 28, 1846, Länghem, Sweden
Died: August 29, 1916 (age 70 years), Pulkovo, Saint Petersburg, Russia
Children: Helge Backlund and Elsa Celsing