Masters of Time

Techniques and algorithms to calculate astronomical events pertinent to the Hebrew calendar.

The book Masters of Time teaches techniques and algorithms to calculate the Molad, times of sunrise and sunset, different twilights, and construction of Hebrew calendars for any location or year. It gives multiple worked-out examples with values at each intermediate step. High schools can use it to teach Excel, calculator methods or programming in any language.

Rabbi Zalmen Stein earned his Bachelor's and Master's in Science and Physics at McGill and Concordia Universities in Montreal, Canada. Rabbi Stein was a high school Rebbe and teacher of hundreds of students in Gemara, Chumash, math, physics, and computer programming courses. He taught at the Lubavitch Yeshiva and Bais Rivkah schools in Montreal for six years, then for 39 years at the Maimonides School in Brookline, MA, founded by Rav Yosef Dov Soloveitchik, Z" L. Then, after Rabbi Stein and his wife retired in Baltimore in 2013 to live near their children, he spent another three years teaching math at Bnos Yisroel School for Girls in Baltimore, MD. Rabbi Stein has always been interested in zmanim in halacha, which he included in many of his lessons throughout his years of teaching. He also used the formulas described within this work to develop calendar and zmanim programs that several shuls and schools use in their community calendars and zmanim schedules