The Tibetan calendar, according to the Kalachakra Tantra, is the induction from the astrology laws and astronomical calendar algorithm. It has been proven over thousands of years that its determination of solar and lunar eclipses and the full moon and obscurity each month are more accurate than the results produced by other calendar algorithms.
Therefore, it is a better choice to do various good deeds on the auspicious days according to the Tibetan calendar.
~ Depicted from Luminous Wisdom Book Series 3