Height of tracers and the correction of the measured solar synodic rotation rate: Demonstration of the method

Two large stable solar filaments were used as test tracers to determine the apparent synodic rotation rate as a function of the central meridian dista nce for several filaments' segments at different heights. An analytic fitti ng procedure was applied to determine simultaneously the real synodic rotat ion rate and the height of the traced filament segments. The determined hei ghts were compared with the values obtained from the widths of filament con tours on the solar disk and with the values obtained by direct measurements at the solar limb. Furthermore, the obtained rotation rates and heights of the filaments' segments close to the filaments' pivot points were compared with the values obtained using two successive central meridian passages. F inally, sources and scales of errors were investigated and possible implica tions on the previous studies of the solar differential rotation were consi dered.