Photometric Distortions Research Articles

Tests of 4 single-stage image intensifier tubes for solar spectroscopy

Atmospheric image degradation can be reduced by shortening the exposure time. Therefore, four single-stage electrostatically focused image intensifier tubes with fiber optic output were tested in the laboratory for their suitability in solar spectroscopy. Under the premise that the spatial and spectral image scales (Capri: 5.9″ mm−1 and 9 mm A−1, resp.) should not be changed by a premagnification, the RCA tube 8605/V1 in combination with Copex Pan Rapid film turns out as the best choice. It yields a resolution of 55 line-pairs mm−1 and a gain of exposure time by a factor of ≈ 14 over Kodak IV-E in the red, with only little increase of photometric noise but appreciable pin-cushion distortion.