The National Optical Astronomy Observatory (NOAO) is the United States national observatory for ground based night time ultraviolet-optical-infrared (OUVIR) astronomy. The National Science Foundation (NSF) funds NOAO to provide forefront astronomical research facilities for US astronomers. However, professional astronomers from any country in the world may apply to use the telescopes operated by NOAO under the NSF's "open skies" policy. Astronomers submit proposals for peer review to gain access to the telescopes which are scheduled every night of the year for observations (with the exception of Christmas and New Year's Eve).
The NOAO headquarters are located in Tucson, Arizona and are co-located with the headquarters of the National Solar Observatory. The NOAO is operated by the Association of Universities for Research in Astronomy (AURA), under a cooperative agreement with the NSF.