Epoch The epoch of the modern Hebrew calendar is 1 Tishri AM 1 (AM = anno mundi = in the year of the world), which in the proleptic Julian calendar is Monday, October 7, 3761 BCE, the equivalent tabular date (same daylight period). This date is about one year before the traditional Jewish date of Creation on 25 Elul AM 1. A minority place Creation on 25 Adar AM 1, six months earlier, or six months after the modern epoch. Thus adding 3760 to any Julian/Gregorian year number after 1178 will yield the Hebrew year number beginning in autumn (add 3759 for that ending in autumn). Due to the slow drift of the modern Jewish calendar relative to the Gregorian calendar, this will be true for about another 20,000 years.
Hours Every hour is divided into 1080 halakim or parts. A part is 31/3 seconds or 1/18 minute. The ultimate ancestor of the helek was a small Babylonian time period called a barleycorn, itself equal to 1/72 of a Babylonian time degree (1° of celestial rotation). Actually, the barleycorn or she was the name applied to the smallest units of all Babylonian measurements, whether of length, area, volume, weight, angle, or time. But by the twelfth century that source had been forgotten, causing Maimonides to speculate that there were 1080 parts in an hour because that number was evenly divisible by all numbers from 1 to 10 except 7. But the same statement can be made regarding 360. The weekdays start with Sunday (day 1) and proceed to Saturday (day 7). Since some calculations use division, a remainder of 0 signifies Saturday.