Astrometric Calibration and Performance of the Dark Energy Spectroscopic Instrument Focal Plane

TL;DR

This paper details the software and methods used to precisely position fibers in the Dark Energy Spectroscopic Instrument, enabling accurate spectral measurements for cosmological studies of the universe's expansion.

Contribution

It introduces the software system and validation methods for fiber positioning accuracy in the DESI instrument.

Findings

Achieved 11μm rms 2-D fiber positioning accuracy.

Validated software performance for large-scale astronomical surveys.

Enhanced the precision of spectroscopic target acquisition.

Abstract

The Dark Energy Spectroscopic Instrument, consisting of 5020 robotic fiber positioners and associated systems on the Mayall telescope at Kitt Peak, Arizona, is carrying out a survey to measure the spectra of 40 million galaxies and quasars and produce the largest 3D map of the universe to date. The primary science goal is to use baryon acoustic oscillations to measure the expansion history of the universe and the time evolution of dark energy. A key function of the online control system is to position each fiber on a particular target in the focal plane with an accuracy of 11$\mu$m rms 2-D. This paper describes the set of software programs used to perform this function along with the methods used to validate their performance.