The experimental design described here allows us to study with 2-Å. bandpass filters the brightness distribution of the green coronal line, the two infrared lines of Fe XIII, and the neighboring coronal continuum. For the first time, in an eclipse expedition, electrostatic cameras derived from the Lallemand type are used; full advantage was taken of their speed, especially in the near infrared spectral range, and their good photometric qualities. They permit the measurement of intensity and polarization of the lines in the corona to a height of 1.25 solar radii above the limb of the sun, with a spatial resolution ≥ (10”)2.
B. Fort, "Studies of Coronal Lines with Electronic Cameras During the Eclipse of 7 March 1970," Appl. Opt. 9, 2643-2647 (1970)