Chandra Dev learned all sastras and arts from his Guru Brahaspati. Later Chandra Dev invited his Guru Brihaspati for a pooja performed by him. As Brahaspati was unable to come, he sent his wife Tara for the pooja.

Chandra Dev welcomed his Guru Pathni Tara and honoured in a proper way. By the way, a new relationship formed between Tara and Chandra Dev. One day, Tara left Brihaspati and went with Chandra. Cunningly, Chandra Dev takes Tara and asked Asura Preceptor Shukra to help for their safety. When Brahaspati along with Indra prepared their army to fight with Asuras to rescue Tara, Brahma intercepts and advised Chandra to return back Tara to Brahaspati. Chandra also agreed.

Even though Tara came back to Brahaspati, she was pregnant by Chandra. The baby born to Chandra and Tara is Budha. Since childhood, Budha raised many questions regarding his birth, father, mother and many other things. Thus Budha (Mercury) is considered as significator of knowledge in Astrology.

When Brahaspati came to know about the father of Budha, he refused to accept Budha and Budha is brought up by Chandra's wives. Some other stories say that Brahaspati accepted Budha and brought up.

As Budha grows up, he doesn't become attached with either Chandra or Brahaspati, but attached more with Shukracharya and Shani. Later, he performed severe penance towards Lord Vishnu and become a navagraha. Athi Devata for Budha (Mercury) is also Lord Vishnu.

In Astrology, Mercury signifies Knowledge, Education, Trade, Mathematics, Computer, Finance, Accounting, Astrology, Communication. If Mercury is powerful and benefic, the native will excel in the above fields. If powerful Mercury joins with Rahu in 7th house, the native may involve in illegal online business.

Mercury is the weakest planet in Astrology. It is fortunate regarding career and politics if Mercury joins with Sun in 10th or in 11th house. But Mercury should not be combust. For Taurus ascendant, Mercury is 2nd and 5th lord. If he sits in 2nd or in 5th house, that will be fortunate for the natives. Those natives could be excellent in the use of words. Example Lord Krishna who is Taurus ascendant having powerful Mercury.