The Jewish calendar is known for its complexity and astronomical precision. It is used by Jews for their religious practices all over the world and, furthermore, it is the official calendar of Israel. The legend says that data for this calendar were given to Moses by the Creator together with the Torah on Mount Sinai. Jews calculate their days from the day of Creation, i.e. from October 7, 3761 BC. The Jewish calendar is luni-solar, its year coincides with the tropical (solar) year and its month - with the synodic (lunar) month. Years are divided into common (12 months) and leap years (13 months). Each month begins with the new moon and each day, according to the Jewish time calculation - at 6 pm. The day is divided into hours in two different ways: “proportional hours” (sha’ot zemaniot) and “regular hours” (sha’ot shavot). Proportional hours are 1/12 of daylight (from sunrise to sunset) and 1/12 of the night. They are used to determine the time of prayers and blessings. A regular hour is a classic 1/24 of the day. Each regular hour is divided into 1080 chelakim. All these values are used both for astronomical and calendar calculations.

Decalogue Rega wristwatch

Decalogue wristwatch

Table clock Shabbat