 both close to the present-day city Xi'an. The longitude of Xi'an is 108.9&deg;E. Hence the local time of the capitals was (108.9/15) hours = 0.3025 days ahead of UT1. Subtracting 0.3025 from <span class="nowrap">JD(M<sub>i</sub>)</span> results in Julian day in UT1. Subtracting the UT1 Julian day of an astronomical conjunction from the UT1 Julian day of the corresponding calendrical conjunction gives the time lag. There were 1764 lunar conjunctions between the month 10 conjunction in <span class="nowrap">N