When a spectral line of wavelength λ=0.59μm\lambda=0.59 \mu \mathrm{m}λ=0.59μm is observed in the directions to the opposite edges of the solar disc along its equator, there is a difference in wavelengths equal to δλ=8.0pm\delta \lambda=8.0 \mathrm{pm}δλ=8.0pm. Find the period of the Sun's revolution about its own axis.