Upper row: 1942, Lyot – 25 drawings, 36 inch refractor, 300-500x magnification.
Lower row: 1950, A Dollfus, 60-inch refractor, 750-900x magnification
Lyot and Camichel, 1942: Map from 12 composites. 23 markings were measured.
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.