Complex sentence: The planetarium opened on 26 January 1957, at which time it was the only planetarium in Brazil; it was opened by Orsini, who subsequently led the initial operation of the planetarium, at the invitation of Maury de Freitas Julião and Wladimir de Toledo Pizza Sobrinho.
Split into simpler sentences: The planetarium opened on 26 January 1957, at which time it was the only planetarium in Brazil. It was opened by Orsini, who subsequently led the initial operation of the planetarium, at the invitation of Maury de Freitas Julião and Wladimir de Toledo Pizza Sobrinho.