A new chapter opens today in the history of the 4-m Mayall telescope, the largest aperture telescope at NSFs Kitt Peak National Observatory (KPNO). Having completed its first 45-year-long assignment, the telescope is now poised to embark on a new mission: creating the largest 3-dimensional map of the cosmos to date. The map will help astronomers chart out the role of dark energy in the expansion history of the Universe.
When the Mayall first opened its eye to the sky 45 years ago, it was one of the largest optical telescopes in existence. Designed to be versatile, its mission was to assist astronomers in addressing the wide diversity of astronomical questions facing the field. Tremendously successful, it played an important role in many astronomical discoveries, such as establishing the role of dark matter in the Universe from measurements of galaxy rotation, and determining the scale and structure of the Universe.
A telescope pivots to study dark energy
Today it sheds its identity as an all-purpose research tool and, reinventing itself, turns to a new dedicated mission that will tackle one of the most profound problems in physics: understanding the mysterious physics of dark energy, an unknown form of energy that is believed to permeate all of space and accelerate the expansion of the Universe.
To prepare for its new mission, the Mayall will close temporarily. Over the next 15 months, it will undergo the largest overhaul in its history in preparation for the installation of the
Dark Energy Spectroscopic Instrument (DESI) , a massively parallel optical spectrometer capable of measuring the spectra of 5000 astronomical objects simultaneously.
https://www.noao.edu/news/2018/pr1802.php