. . . . . "Pioneer astronomers"@en . "Pioneer astronomers" . . "How our knowledge about the heavens has been increased slowly but steadily by men from Copernicus to Smith & Baade."@en . . . . . . . "Biography"@en . "Biography" . "Juvenile works"@en . . "Juvenile works" . . . . "Pioneer Astronomers" . "Astronomy through seventeen of the men who developed it, from Copernicus to the pioneers of radio astronomy. Grades 6-9. For contents, see Author Catalog." . . "Astronomes Ouvrages pour la jeunesse." . .