temps solaire vrai

OBS: L'intervalle de temps entre le passage inférieur du Soleil et une autre de ses positions quelconques, exprimé en fractions du jour solaire vrai (heures, minutes, secondes solaires vraies), s'appelle ""temps solaire vrai"" (...)

OBS: Just a sidereal time is reckoned by the hour angle of the vernal equinox, so ""apparent solar time"" is determined by the hour angle of the sun. At midday, apparent solar time, the sun is on the meridian. The hour angle of the sun is the time ""past midday"" (...) It is convenient to start the day not at noon, but at midnight. Therefore the elapsed apparent solar time since the beginning of a day is the hour angle ""plus"" 12 hours.