About 700 stars, mostly OB-stars, were observed by the author at the former Leiden Southern Station at Hartebees poortdam, South Africa, in the observing seasons 1965, 1968, 1969, 1974, 1977, 1978. Observations were made in the five channels of the Walraven photometric system. Due to weathering of the telescope mirror the W channel gave no reliable results for the faintest stars (m=11mag); in these cases the U-W colour index is not given. The change in sensitivity in the V channel, supposedly having occurred in 1968, was not recognised. For a description of the Walraven VBLUW photometric system, see e.g.