The following image is a recent high-resolution map of Maximum Usable Frequencies (MUFs) for 3,000 kilometer radio signal paths. It is also a map showing the current location of the auroral ovals, the sunrise/sunset terminator and the regions of the world where the sun is 12 degrees below the horizon (which estimates the gray-line corridor where HF propagation is usually enhanced).
The foF2 values used in the mapping process are based on the median of the last 2 hours of station data (4 values per hour). This was done to try to reduce the effect of bad foF2 values. This may mean that the map may lag actual ionospheric behaviour by about an hour, particularly at local dawn periods.
