Big Dipper Over the Tibet Plateau

December 01, 2013

Big dipper over delinha

Photographer: Jeff Dai
Summary Authors: Jeff Dai; Jim Foster

The photo above shows the Big Dipper as observed at the Delinha Observatory, located at the eastern Tibetan Plateau in Qinghai province of China, on the evening of Oct 4, 2013. Delinha 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 found 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, the meteor trail (top center) and the astrophotographer, lower left, preparing to explore the night sky.

Photo Details: Camera: Canon EOS 6D; Lens: EF50mm f/1.4 USM; Focal Length: 50.0mm; Aperture: f/2.5; Exposure Time: 13.000 s; ISO equiv: 6400; Software: Adobe Photoshop CS6 (Windows).