The determination of action spectra for biological photoreactions requires that large areas be irradiated uniformly at high intensities and with narrow band widths for the resolution of spectral details: When the material is changing irreversibly with time or when long irradiation periods are required, it may be necessary to irradiate samples at ten or more different points in the spectrum simu...

A digital CCD all-sky spectrograph was made by the Polar Geophysical Institute (PGI) to support IPY activity in auroral research. The device was tested at the Barentsburg observatory of PGI during the winter season of 2005– 2006. The spectrograph is based on a cooled CCD and a transmission grating. The main features of this spectrograph are: a wide field of view (∼180), a wide spectral range (3...