Helioseismic Constraints: Past, Current, and Future Observations

Abstract

I will review the history of the helioseismic observations since the beginning of the field. I will explain how each instrument was designed based upon the required observables, and to which modes these instruments are sensitive. The impact of these sensitivities on the rotation and structure inversion will be developed. I will conclude with what remains to be done in this field for the future of detection.