The spectrum of R Geminorum at its unusually bright maximum in 1955

P. C. Keenan, R. G. Teske
1956 Astronomical Journal  
tern across the objective. Since the velocity of the objective image can be determined from its displacement during the known exposure time, the velocity of the pattern required to give the observed inclination of the bands can be readily calculated. The direction of pattern motion was found to be parallel to the bands, in agreement with the interpretation of earlier photoelectric observations.
doi:10.1086/107316 fatcat:3ljrbmhge5afdepupsehfc22j4