Radial velocity curves of IGR 1955+0044. Bottom panel: single Gaussian measurements of H_β fitted with a sine curve are shown. The filled squares are data obtained at SPM; the open squares are from MDM. Top panel: the measurement of the narrow component of the H_α line wherever we were able to distinguish it in the line profile, is shown. The sine curve with fixed period determined from the H_β analysis was used to fit to these points. There is a small phase shift of the H_β RV curve from being totally opposite to that of H_α.