Early history of Arecibo Observatory

Altschuler and Salter reply: We thank both correspondents for their interesting comments. To Michael Dowe we note that the directors of the Arecibo Observatory through the 1960s were William E. Gordon (1960–65), John W. Findlay (1965–66), Frank D. Drake (1966–68), and Gordon H. Pettengill (1968–71). We emphasize that our article concentrated on major astronomical contributions from the observatory over its 50 years of operations. For an excellent account of its contributions to atmospheric and ionospheric physics, we recommend John Mathew’s article “A short history of geophysical radar at Arecibo Observatory.”¹