Big Dipper over Delingha Observatory

The Big Dipper as observed at the Delingha Observatory, located at the eastern Tibetan Plateau in Qinghai province of China. The high elevation, dry atmosphere, and nice weather conditions make Delinha an excellent place for millimeter-wave radio observation. The primary facility of the observatory is the 13.7m radio telescope inside the dome. Delingha is a Mongolian word meaning the golden grassland where the Sun rises. The Dipper is the most recognizable asterism in the northern night sky. It consists of the seven brightest stars in the constellation Ursa Major – the Great Bear. The four brightest Dubhe, Alioth, Alkaid and Mizar have magnitudes, ranging from 1.8 – 2.1, and are at similar distances from us — about 80-125 light years away. They’re all considerably brighter than other stars in this swath of the sky. The two end stars in the Dipper’s bowl are the pointers to Polaris — off the top of the frame. Note that Mizar, the middle star in the Dipper’s handle, has a companion star (Alcor) that’s visible with the unaided eye outside of urban areas. Also notable is the greenish airglow in the background sky, as well as a satellite trail (top center) and the astrophotographer (lower left) preparing to explore the night sky.