Parameters of dark mottles based on high resolution optical spectra

High resolution optical spectra of hydrogen and calcium lines observed with the Echelle spectrograph of the VTT at Sacramento Peak Observatory were analyzed. The observed line profiles in some parts of dark chromospheric mottles are to be matched with theoretical ones using the cloud model and several parameters (e.g. the temperature, gas pressure, flow velocity) are to be derived. Individual steps of the procedure, as well as crucial problems are discussed.