ABSTRACT
This chapter explores early spectroscopic foundations on which much of modern cosmology. Indeed, the measurement of redshifts for galaxies and the assumption that these are Doppler shifts is so fundamental to cosmology that it is sobering to consider how much more limited our knowledge of the universe would be if the Doppler effect had somehow escaped inclusion in the astronomers’ toolkit. The validity of the Doppler effect was a matter of considerable controversy for several decades. The literature on the validity of the Doppler effect from the 1850s to 1870s is particularly rich and interesting, and often contentious. Once the validity of the Doppler effect had become fully accepted and photography had been established as an indispensable technique in stellar astronomy, many observatories undertook major programs in photographic Doppler shift measurements for stars. The discovery of helium was one of the early triumphs of astronomical spectroscopy.
