Histograms of r_sol for w_SB equal to 2500, 33 000, 89 000, 150 000, and 650 000 km, shown as brown, blue, green, red, and purple lines, respectively, for an SB trigger in the height range 5–10 Mm. The grey-shaded area encapsulates r_sol values accessible with our existing EUV instrumentation; the smallest r_sol in this area can be measured by the Extreme Ultraviolet Imager on board Solar Orbiter.