The Skibotn CCD All-Sky Imager (SCASI) consists of a peltier-cooled bare CCD camera fitted to a twin-mirror all-sky optic (180 degree field of view). The main purpose is to perform cloud cover detection in a supporting role for the FPI and DASI experiments. Manually, this is done by looking for stars, though we also use a computer algorithm to search for clear periods. Images of 30 second exposure are taken every 3 minutes. The aurora is also clearly seen. Unmanned observations are made for all dark periods.
In addition, an optional filter may be inserted. Mesospheric OH at 843 nm is recorded in order to study the effects of precipitation with IRIS. Exposures of 5 minutes are used.
Figure: White-light all-sky image of the aurora. Note the trees on the horizon and the background stars. The blind spot in the middle is an artifact of the type of mirror optic used.
M. J. Kosch