Measurements of the Solar Gravitational Deflection of Radio Waves in Agreement with General Relativity

In two experiments in 1974 and 1975, utilizing a radio interferometer of 35-km base-line, the relative positions of three radio sources were monitored over a period of a month when the sun was within 10 deg of the sources. The mean gravitational deflection is 1.007 ± 0.009 (standard error) times the value predicted by general relativity. These results exclude the Brans-Dicke theory of gravitation with a scalar coupling constant $\omega <23\mathrm{}$ at the 99% confidence level.