The calcium K-line profiles as function of latitude and solar cycle phase Original Research Article

We have monitored the Calcium K-line profiles on daily basis at all the 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. The spectra were recorded at a dispersion of 9.34 mm/Å on 35 mm Kodak 103-a0 film for the time interval of 1986–95. Now we obtain the spectra using 1K × 1K peltier cooled CCD Camera. We plan to use the data to study possible long term variation in chromospheric rotation rate, differential rotation rate, variation in background flux, and changes in polar regions with the phase of the solar cycle through various parameters of this line.