The history of astronomy has recently been invigorated by approaches first used in social and cultural history. Historians of science have been sourcing old ministerial reports, journals, books, and institutional documents to provide new interpretations of the role of national astronomical observatories at the beginning of the nineteenth century. The same movement is happening in the Brazilian historiography of science. This project follows the trajectory of a man responsible for formulating the first project to build a national observatory in Rio de Janeiro in 1827, Candido Baptista de Oliveira. Military engineer, professor, politician and man of science, he described the project in “Memória sobre o estabelecimento de observatório no Rio de Janeiro,” published in 1828. Oliveira’s proposal is examined in the context of Brazilian Independence (1822) and the founding of several scientific institutions by this new empire. Taking a wide perspective on Oliveira’s proposal to build an observatory, this project considers that his drawing on connections with the military and other scientific institutions was not contradictory, but rather a practical way to improve the empire’s policies as well as provide benefits for civilian society.