Interferometric investigations of sources of OH emission-1. Observations with an interferometer baseline of 7X 05 wavelengths

The bright OH emission sources W4, W24B2, W49, W5i and W75 (DR2I) have been studied with a six-channel interferometer of baseline 7 x i wavelengths operating between Jodrell Bank and Malvern. Measurements of the relative phase between different spectral components of a given source were used to find their relative positions. The angular diameters of individual components were not resolved at this interferometer spacing. An accuracy of about 0#. 01 arc was achieved for the relative positions of the brighter components of W3, and the eleven spectral components were found to be scattered over a region of diameter 2 arc. There appears to be some clustering of components which have similar velocities and polarizations.