* The real spectra is not very close to any blackbody spectra (slightly different shape) * The measurement
devices do not agree * The radiation temperature
of the
center of the solar disk is higher than the apparent temperature near the edge * The temperature
of the outer corona is more than 1,000
hotter than the «surface» * The Sun does not have a surface * The distance between the Earth and Sun varies (the orbit is an ellipse), and different references handle this differently