V.M. Slipher and the Development of the Nebular Spectrograph

TL;DR

This paper reviews Vesto Slipher's pioneering work on nebular spectrograph development and its impact on measuring galaxy velocities, which was crucial for establishing the universe's expansion.

Contribution

It provides a historical analysis of Slipher's early contributions and how they influenced subsequent discoveries in cosmology during the 1930s.

Findings

Slipher's work defined key factors in nebular spectrograph performance.

His early galaxy Doppler shift measurements were foundational for cosmology.

The development of the velocity-distance relationship confirmed the universe's expansion.

Abstract

Vesto Melvin Slipher was the first astronomer to clearly define the factors that determine the "speed" of a nebular spectrograph. This brief historical summary recounts the way these ideas developed and how Slipher's early work on galaxy Doppler shifts was so quickly extended in the 1930's when Milton Humason and Edwin Hubble at Mt. Wilson Observatory began to push the velocity-distance relationship to such a depth that no one could doubt its cosmological significance.