I´m very interested in understanding how the shift time correction factor is calculated. I understand the need of calculating the solar geometry at the correct time label interval, but I don´t know how you are doing this minute-correction. Is it based on the imported TMY irradiance values, trying to make the ratio between imported irradiance value and clear sky value equal to 1 in a clear sky day? Is it based on solar geometry?
I would really appreciate if you could provide some further information on this time adjustment.