Interview with Tsultrim Gyatso of Tibetan Service, who had studied Astro-science extensively in Tibet. Gyatso said that Tibetan calendar-reading is based on the principles of Astro-science and dates back to ancient times, even before the birth of Christ. He explains that the Astro sciences of calendar-making, astronomy, astrology, and mathematics touch many aspects of Tibetan life. This knowledge presents the calculations for the ephemeris to give the position of the planets, as well as those for making the calendar and predicting eclipses. It also includes the astrological calculations for personal horoscopes. Gyatso considers it a relevant branch of studies for Tibetan students, and not that difficult if you have studied Mathematics and have an inquisitive mind.