Auroral spectrograph

The auroral spectrograph consists of a large fish-eye lens (180-degree FOV, f=6 mm, F1.4), a slit which passes the light from the sky along meridian direction, a collimating optics, a grism with 600 gr/mm, an imaging optics, and a digital camera with a bare, back-illuminated CCD chip of 512 x 512 pixels. The spectrograph covers a wavelength of 420-740 nm with spectral bandwidth of 0.6 nm, and with spatial resolution of 0.18 x 0.18 degrees. The sensitivity is 0.06 counts/pixel/Rayleigh/sec which enables sampling rate of a few seconds per image. This also contributes to the collaborative study with the EISCAT Svalbard Radar (ESR) and other ground-based observations.