The Vedic night observers divided the circle of the sky into 27 sections. These divisions, separate from the Zodiac Signs, were used in ancient times to mark the movement of planets, especially the Moon against the main star groups that were located in or around those 27 sky sections. Each fixed star group, or Nakshatra, had a bright, primary star to help observers find it. This was called the Yoga Tara. It was once believed to mark the union (yoga) or boundary between Nakshatras.
The Moon sign prediction and the Star signs astrology are equally important because when the Moon crosses over the Yoga Tara (Star) or its group, it designates a specific Moon Nakshatra and signals the time to perform certain rituals (e.g.; yagnas) or to start or stop specific events (muhurtha).
The core understanding of personality and behavior is derived from the Horoscope Chart/ Birth Chart but is supplemented by a finer understanding of the Moon's effects given by the Nakshatras or Moon signs. The Nakshatras are often identified relative to their position within the Horoscope Chart- as sub-constellations within the 12 signs of the Solar Zodiac.
Horoscope chart can be in a way said to be the image of yourself. Your Horoscope Chart is drawn from calculations based upon the date, time, and place of your birth. Your birth details are the most important factor in Vedic astrology. An astrologer analyzes this horoscope chart and examines the patterns and factors which describe your personality and needs. .
