Atmakara is derived from two words, “Atma”, which means soul and “Karaka”, which means significator. Hence, Atmakaraka means the soul significator, the planet that holds the lesson that the soul is here to learn. Atmakaraka planet represents the personality of one’s soul and the way the soul thinks and wishes to fulfil.
Sun is the actual significator of the soul and hence, is known as the original Atmakaraka. The remaining seven planets, Mercury, Venus, Mars, Jupiter and Saturn, are considered Chara Atmakaraka. Even Rahu is a part of this because Rahu brings past life lessons into this life, just like other planets. Rahu is an unfulfilled desire that needs to be fulfilled in this life.
If someone is questioned about their atmakaraka planet, it is incorrect to say that it is Sun unless Sun is under particular circumstances. It is because the planet with the highest degree is considered as 'Chara' Atmakaraka. Each planet can be between 0-30 degrees, and the planet that holds the highest degree amongst all the planets becomes the Chara Atmakaraka. This way, Sun for someone can become not just Atmakaraka, but also the Chara Atmakaraka.
While determining one’s Chara Atmakaraka, it is essential to note that Rahu is a retrograde planet, meaning that it moves backwards. Hence, Rahu’s mentioned degree is deducted from 30 to arrive at its actual degree.
Determining the atmakaraka planet helps the native to understand his soul’s purpose and what he is here to achieve. Every planet has its own feature, and hence the lessons to be learnt will also be different.
SUN - Finding success, fame and power without ego.
MOON - Finding Happiness in loving selflessly.
VENUS - Finding love in everything but finding it in balance and not in excessive ways.
MERCURY - Communicating in a divine manner, speaking the truth and using intelligence to help people and not to deceive people.
MARS - Learning to defend the weak, learning to be peaceful while having little to no anger towards the things that may make one angry.
JUPITER - Learning the meaning of God, spirituality, and human nature and learning from your children, spouse and teachers without wanting to get something in return.
SATURN - Learning to be disciplined, to learn the reality of the world rather than living in a dream world, learning to find happiness in loneliness.
RAHU - Letting go of desires and not being obsessive about a quick route to everything. Instead, learning to be patient, having reasonable desires and not obsessing about what Rahu represents in your birth chart.