The TST function calculates the True Solar Time (TST) according to DIN EN 17037 from UTC (Coordinated Universal Time). At 12:00 TST the sun is at \alpha_S = 180\degree. The default geographical settings are set in the file “LT_location.mat”. Change the settings to your preferred location and set the file to read-only in order to prevent your settings from being overwritten with the default values in future versions.


t = TST(date,utc,geolength,geowidth)


tReturns the True Solar Time in 'hh:mm:ss' format.
dateSpecifies the date in '' format, default: current day.
utcSpecifies the UTC time in 'hh:mm:ss' format, default: current time.
geolengthSpecifies the geographic length, default: 13.326 (Berlin). You can change the preference in the “LT_location.mat” file.
geowidthSpecifies the geographic width, default: 52.514 (Berlin). You can change the preference in the “LT_location.mat” file.


True Solar Time in Berlin at ‘21.05.1987’ – ’11:03:22 UTC:

t = TST('21.05.1987','11:03:22')


t = 12:00:00

Note: to determine noon UTC time, use the south function.

True Solar Time in Athens at ‘21.05.1987’ – ’11:03:22 UTC:

t = TST('21.05.1987','11:03:22',37.978,23.728)


t = 13:38:37


DIN EN 17037:2019-03: Daylight in buildings. 2019.

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