Plate 19.—Chart of Mars by Dr. J. H. Focas, showing the fine structure of the dark areas, based on visual and photographic observations with the 60 cm refractor at the Pic du Midi Observatory in 1958.
Mars — map
Drawing by J. H. FOcas, Pic du Midi, 1958
Jean-Henri Focas
Source: A. Dollfus: Visual and photographic studies off planets at the Pic du Midi. In: Planets and Satellites, GP Kuiper and B Middlehurst, eds. Chicago Univ Press 543-571.