The Stellar Observations Network Group (SONG) is a low-cost ground based international collaboration aimed at two cutting edge problems in contemporary astrophysics in the time-domain: 1) Direct diagnostics of the internal structure of stars and 2) Search and study of extrasolar planets, possibly in the habitable zone. The general plan has been to set up a network of 1m telescopes uniformly distributed in geographic latitude (in both hemispheres). China joined the collaboration (initiated by Danish astronomers) at the beginning in 2009. In addition to SONG's original plan (http://song.phys.au.dk), the Chinese team proposed doing work in photometry in parallel with a sub-network of telescopes associated with SONG in the northern hemisphere.

This project is called 50BiN (50cm Binocular Network, previously known as mini-SONG). This sub-network would enable a large field photometric capability for the network, therefore maximizing the potential of the network platform. The network will be able to produce nearly continuous time series observations of a number of selected objects with high resolution spectroscopy (SONG) and accurate photometry (50BiN), and to produce ultra-high accuracy photometry in a dense field to look for microlensing events caused by planetary systems. This project has great synergy with Chinese Astronomical activities in Antarctica (Dome A) and other similar networks (e.g. LCOGT).