engleski

A method to determine the solar synodic rotation rate and the height of tracers

The dependance of the measured apparent synodic solar rotation rate on the height of the chosen tracer is studied. A significant error occurs if the rotation rate is determined by tracing the apparent position of an object above the photosperic level projected on the solar disc. The center-to-limb variation of this error can be used to determine simultaneously the height of the object and the true synodic rotatition rate. The apparent (projected) heliographic coordinates are presented as a function of the height of the traced object and the coordinates of its 'footpoint'. The relations obtained provide an explicit expression for the apparent rotation rate as a function of the observed heligraphic coordinates of the tracer, enabling an analytic least-squares fit expression to determine simultaneously the real synodic rotation rate and the height of the tracer.

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