Skanda Hora is the legendary first book on Hindu astrology. It is the first text and the foremost treatise of Nirayana astrology referred to as the Mahopanishad of the Atharva Veda dating back to 3000 B.C. This text on Hindu predictive astrology written in SanskritSloka-format by Skanda, also known as Subrahmanya, Kandaswamy, Kartikeyan and Murugan, is also known as Jyotishmati Upanishad
The complete text of Skanda Hora is now not available, what is known is from its several and numerous slokas cited by other ancient texts.  It is the root of all other Horas, and along with Surya Siddhanta gives maximum importance to the rhythm of the solar system, breath pattern and minute divisions of time which indicates its origination from and affiliation to the Yogic and Tantric experiences that were probably associated with the Indus Valley Civilisation. The present day Hindu astrology is an extension of Skanda Hora.