Kitt Peak Mayall 4 m, visible light. Credit: KPNO/NOIRLab/NSF/AURA/M. T. Patterson (New Mexico State University) Image processing: T.A. Rector (University of Alaska Anchorage/NSF NOIRLab), M. Zamani & D. de Martin (NSF NOIRLab). Licence: CC BY 4.0. Source