English: The Sun as seen in radio waves from 17 GHz down to 80 MHz. From left to right, the observations were recorded by the Nobeyama Radioheliograph (NoRH), Very Large Array (VLA), Nancay Radioheliograph (NRH), and Murchison Widefield Array (MWA). The NoRH and MWA images were taken on the same day, and the VLA and NRH are on different days. The NoRH and VLA images are in false color, and the NRH and MWA images are in grayscale. The first two on the left are dominated by gyromagnetic emission from the chromosphere, transition region, and low-corona, while the three images on the right are dominated by thermal bremsstrahlung emission from the corona, with lower frequencies being generated at larger heights above the surface. Solid circles in the right three panels correspond to the size of the Sun seen in visible light.