= Edward Fomalont
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<Edward Fomalont> led a precise radio test of <gravitational lensing> near the <Sun>. The team used the <Very Long Baseline Array> to compare four radio sources over eighteen days in 2005, measuring changes in their relative apparent directions as the <Sun> moved across the sky.
Observations at several <frequencies> helped assess <refraction> in the <solar corona>. The 43 <gigahertz> data, sufficiently far from the <Sun>, largely avoided that disturbance. Fitting the gravitational signal gave the post-Newtonian parameter $\gamma=0.9998\pm0.0003$, consistent with <general relativity>. The experiment illustrates why controlling propagation through <plasma> matters even in a test of <gravity>.<Progress in Measurements of the Gravitational Bending of Radio Waves Using the VLBA by Edward Fomalont and others>[Abstract: four-source experiment, frequencies, coronal refraction and fitted gamma]{ref}
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