The Sierra Nevada Observatory (Spanish; Castilian: '''Observatorio de Sierra Nevada'''; OSN; code: J86) is located at Loma de Dilar (2896 m altitude) in the Sierra Nevada mountain range, in the province of Granada, Spain; established in 1981. It is operated and maintained by the Instituto de Astrofísica de Andalucía (Institute of Astrophysics of Andalusia - IAA) and contains two Nasmyth telescopes with apertures of 1.5 and 0.9 metres.