Anton Pannekoek (1873-1960) was both an innovative astronomer and an influential Marxist. In this article we will investigate both his Milky Way research and Marxist philosophy, with special focus on his ideal scholarly persona and the epistemic virtues he advocated in his research. This focus allows us to place Pannekoek in the larger development of science methodology during the nineteenth and early twentieth century and, most importantly, offers insight into how Pannekoek’s scientific and socialist research were related.