English: Kitt Peak National Observatory (KPNO), a Program of NSF’s NOIRLab, is seen in this daytime aerial panorama of the Arizona-Sonoran Desert on the Tohono O'odham Nation in Arizona. The two largest telescopes, towards the center of the image, are the Nicholas U. Mayall 4-meter Telescope (center) and the UArizona Bok 2.3-meter Telescope (right). The Mayall telescope is currently fitted with the Dark Energy Spectroscopic Instrument (DESI), led by the US Department of Energy. The DESI Survey will measure the effect of dark energy. This mysterious energy is causing the expansion of the Universe to accelerate, instead of being slowed by the effects of gravity as initially expected by researchers before observations of distant objects were possible. By collecting the optical spectra of tens of millions of galaxies and quasars, researchers will use the DESI Survey to construct a 3D map of the nearby Universe and measure its expansion.This image was taken before the 2022 Contreras Fire, which affected KPNO. Read more here.