Photoelectric radial velocities, paper VI. Heard's IAU standard stars.

Fourteen of the 24 `ninth-magnitude' radial-velocity standards proposed by Heard have been observed. One of them is shown to vary in velocity, in addition to two already rejected by Heard for the same reason. The photoelectric observations give accidental errors substantially smaller than those of the published standard velocities. Criteria appropriate to the selection and adoption of future standard stars are suggested.