An atomic vector magnetometer and magnetometric methods based on atomic clock transitions unaffected by magnetic field strength for increased quantum coherency time, resulting in improved sensitivity over conventional Zeeman-based atomic magnetometry, where coherency is restricted by sensitivity to magnetic fields. Instead of measuring magnetic field strength in the direction of the quantization axis, as in Zeeman magnetometry, magnetic field strength is measured substantially orthogonal to the quantization axis, via determining the angular displacement of the quantization axis by the magnetic signal field, which is detected by changes in atomic state populations as the quantization axis is rotated relative to the excitation polarization. In addition, the present invention measures magnetic fields instantaneously rather than via accumulated phase shift over time, as in Zeeman magnetometry, thereby providing measurement and spectral analysis of time-varying magnetic fields.