There is a proverb - "Well begun, half done" this is the theroy of Veda. A work done in good time has more assurance for success. therefore Veda always suggest to find an auspicious time for every important work you plan to do and you wish to have success. these auspecious days are called Muhurta. In muhurta the astrologer checks every day in your given option with certain auspicious elements like - Nakshatra, Tara, Ascendant, Moon sign, Planetary position, Yoga, Karan, Day and several other things including the pure period of Jupiter, Venus, sun, Moon. The most important is that a muhurta for a specific purpose can be bad for another purpose. Therefore Vedic Astrology adopts different technics of defining good muhurta for each purpose.