The Dark Energy Spectroscopic Instrument (DESI) is under construction to measure the expansion history of the Universe using the Baryon Acoustic Oscillation technique. The spectra of 35 million galaxies and quasars over 14000 sq deg will be measured during the life of the experiment. A new prime focus corrector for the KPNO Mayall telescope will deliver light to 5000 fiber optic positioners. The fibers in turn feed ten broad-band spectrographs. We will describe the methods and results for the commissioning instrument metrology program. The primary goals of this program are to calculate the transformations and further develop the systems that will place fibers within 5μm RMS of the target positions. We will use the commissioning instrument metrology program to measure the absolute three axis Cartesian coordinates of the five CCDs and 22 illuminated fiducials on the commissioning instrument.

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Rebecca A. Coles, David Brooks, Mark Derwent, Paul Martini, Thomas O'Brien, Ashley Ross, and Suk Sien Tie, "DESI commissioning instrument metrology ," Proc. SPIE 10706, Advances in Optical and Mechanical Technologies for Telescopes and Instrumentation III, 107061L (Presented at SPIE Astronomical Telescopes + Instrumentation: June 13, 2018; Published: 10 July 2018); https://doi.org/10.1117/12.2312592.