The expedition of the Harvard College Observatory, the Smithsonian Astrophysical Observatory, and the National Geographic Society to Miahuatlán, Mexico, to observe the total solar eclipse of 7 March 1970, is described. Instrumentation included a coronal spectrograph, television cameras recording on videotape, telescopes for photography of coronal polarization, and cameras for direct photography. Photographs and preliminary microphotometer tracings are included.
D. H. Menzel and J. M. Pasachoff, "Eclipse Instrumentation for the Solar Corona," Appl. Opt. 9, 2626-2630 (1970)