Survey Operations for the Dark Energy Spectroscopic Instrument

Understand

The Dark Energy Spectroscopic Instrument (DESI) survey is a spectroscopic survey of tens of millions of galaxies at $0 < z < 3.5$ covering 14,000 square degrees of the sky.

• In its first 1.1 years of survey operations, it has observed more than 14 million galaxies and 4 million stars.
• We describe the processes that govern DESI's observations of the 15,000 fields composing the survey.
• This includes the planning of each night's observations in the afternoon; automatic selection of fields to observe during the night; real-time assessment of field completeness on the basis of observing conditions during each exposure; reduction, redshifting, and quality assurance of each field of targets in the morning following observation; and updates to the list of future targets to observe on the basis of these results.