Light curves for three
visual observers were compared with the Landis photoelectric light curve of X
Cygni (see Landis, H. J., this issue). It was shown that the results of one
visual observer agreed closely with the photoelectric curve. The curves obtained
by the other two observers agreed closely with each other, but were about 0.3
mag. below the photoelectric results. This indicated that "Observer
Constants" could be applied to the two visual curves to bring them into
approximate agreement with the photoelectric curve.