A 12-month year in the Hebrew Calendar. A deficient common year contains 353 days, a regular common year contains 354 days, and a perfect common year contains 355 days.
A measurement of time in the Hebrew Calendar equating to 1080 parts or 3600 seconds. The use of hours has the advantage of eliminating fractions. Hours are calculated from 6 PM; thus 6 hours equates to 12 Midnight, 12 hours equates to 6 AM, and 18 hours equates to 12 Noon.
A 13-month year in the Hebrew Calendar. A 30-day month called Adar I is added in years 3, 6, 8, 11, 14, 17, and 19 of each 19-year cycle. The result is a year with 383, 384 or 385 days. Also referred to as a leap year.
The calculation of the average conjunction of the moon with the earth and the sun; it is based on the mean or average length of the lunar month, which is 29.53059 days. The Molad is not the astronomical conjunction.
A measurement of time in the Hebrew Calendar equating to 3 1/3 seconds. There are 18 parts to a minute and 1080 parts to an hour.
A one or two-day adjustment to the calculation of the Molad of Tishri. These adjustments enable the process of calculating the Molad to consistently achieve the greatest degree of accuracy in relationship to the cycle of the moon.