The Dark Energy Spectroscopic Instrument (DESI)

The recently commissioned Dark Energy Spectroscopic Instrument (DESI) is a fiber-fed spectroscopic instrument installed on the 4-meter Mayall telescope at Kitt Peak National Observatory (KPNO). It is now embarking on an ambitious survey to explore the nature of dark energy with spectroscopic observations of 35 million galaxies and quasars in just five years using the Baryon Acoustic Oscillation method to measure distances from the nearby universe out to redshift z = 3.5, and Redshift Space Distortions to measure the growth of structure and probe potential modifications to general relativity. In this talk we describe the significant instrumentation development for the 4-m Mayall telescope at Kitt Peak National Observatory that enables the DESI survey.