Day of the week:
Julian dates assign a unique number to each calendar day. The Julian day number counts the number of days since noon on January 1, -4712 (astronomical calendar) or January 1, 4713 BC (civil calendar). This system, widely used by astronomers, was proposed by Julius J. Scaliger in 1583. Hours and minutes are counted as fractions of a day since the last noon (Universal Time).
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