Variation in the network flux as derived from the Calcium K-line profiles as function of latitude and solar cycle phase Original Research Article

We have obtained the Calcium K-line profiles, on daily basis, at all latitudes, while integrating the spectrum over the visible longitudes of the Sun by moving a ∼340 mm solar image at a uniform speed in the E–W direction of the Sun. The spectra were recorded at a dispersion of 9.34 mm/Å on 35 mm Kodak 103-a0 film for the time period of 1986–95. Then we started to obtain the spectra using 1k × 1k liquid cooled CCD Camera. We plan to study possible long-term variations in the chromospheric rotation rate, differential rotation rate, and changes in Polar Regions with the phase of the solar cycle using various parameters of this line. Here we discuss the variation in K-line flux, K1-width and K2-width in terms of the contribution from plages and variation in the network flux with the phase of the solar cycle.