Example of apparent velocity shift in magnetically sensitive spectral lines. Black solid line: spectrum containing four lines of molecular FeH without magnetic fields in a T = 3700 K atmosphere; red dashed line: same spectral lines influenced by a magnetic field of B = 1000  G. Inset shows auto-correlation function of the field-free case (black solid line) and cross-correlation between field-free spectrum with magnetic case spectrum (red dashed line).