Refraction in the corona of four radio ray paths (solid lines) with different viewing angles to an observer on Earth as determined from ray tracing simulations for a frequency of 55 MHz and a barometric density profile (Newkirk 1961) with α = 3.3. Fundamental radio emission generated in the plane of sky at a radial distance from the Sun r_f is scattered at the distance r_ref and refracted to Earth where its observed at a radial distance r_obs . The distance r_obs is given by the intersection of the plane of sky with the nonrefracted path indicated by the dashed line.