The Fast Imaging Solar Spectrograph(FISS) is an instrument designed to study the fine-scale structure and dynamics of plasma in the chromospheric features. It was developed by the Solar AStronomy Group of Seoul National Univeristy(SNU) in collaboration with Korea Astronomy and Space Science Institute (KASI)
. The instrument was installed on a veritcal table of Coude lab of the 1.6m Goode Solar Telescope (GST, initially NST) in Big Bear Solar Observatory (BBSO)
on May 14, 2010. With the aid of adaptive optics (AO), the instrument does imaging of high quality, based on a fast scan of the slit across the field of view. FISS usually records the Hα(6563Å) and the CaII8542Å band simultaneously using two CCD cameras.