Synastry means analysing human relationship through astrology. In Vedic System, the most common method to judge compatability between two individuals is through Goon Milan or what we can say is the matching the 8 main factors of life from mental compatability to physical compatability and longevity of relationship. This system is based on nakshatra. In western Astrology the concept of Composite chart is well known. The same composite chart can be made in vedic system and analyse for relationship compatability. The ascendant shows how you view each other as couple and how others see you as a couple. The second house shows your financial possessions and how do you share your possessions with each other. The Third house is the house of communication and this house shows how do you communicate with each other and understand each others emotions. The Fourth House indicates whether your relationship has potential for the long-term. Ideally, a moon in this house is a strong sign for a successful, lasting relationship. Fifth House indicates your shared activities, learning as a couple and potential to have children. Sixth House shows where you as a couple are challenged in your relationship, your arguments and health after being together. Seventh House is the house of partnership, it shows as a couple how compatible you will be and how the relationship will be. Eighth House: Eighth house is the house of sex, inheritance and loss. It shows how intimate the relationship will be in regards to physical relationship. Ninth House is the house of dharma, it shows as a couple how two of you will influence each other to follow rightous path and believe in religion / god. 9th house also deals with how you two share adventures, travels. Tenth House reveals the status of you as a couple and how you approach life. Eleventh House indiacates the social life of your relationship and how you move in society, your common friends and your desire fulfilment as a couple. Twelfth House is the house of loss, expenditure, and bed pleasure. It tells how you enjoy your private life, your expenditure and the hidden feelings, psychic connection you two have with each other. You have to judge the planetary position in these houses and 12 signs, the aspect and conjunction of each planet. Writing everything is not possible on facebook as facebook has limitations