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Ask the Rabbi: answers from Project Genesis rabbis
How do the Jews measure time?
An hour is defined as 1/12 of a day; thus the length of an hour varies with the seasons and with latitude. To define periods of time more precisely, an hour is divided into 1080 (3×360) units, called chalakim (“parts”).
When the Torah talks about the nineth hour, what time of the day is it?
Have to see the exact passage to be sure, but usually it means the 9th hour of daylight, having divided the daylight hours into 12 equal parts.