The Jewel of Auspicious Moments

The Sub-divisions of Astrology

For each of the four Vedas, a distinct branch of astronomical science is found: the Rig-Jyotisha, the Yajur-Jyotisha, the Sama-Jyotisha, and the Atharva-Jyotisha. Over the course of time, this science underwent significant development. As time passed, this discipline was divided into three main branches literally "trunks" or "skandhas": Mathematical Astronomy (Siddhanta), Omens and Mundane Astrology (Samhita), and Natal Astrology (Hora). As stated by the sage Narada:

The supreme science of astrology is the pure eye of the Veda,
consisting of three branches: Siddhanta, Samhita, and Hora.

Furthermore, in the text Prashna Marga A famous 17th-century South Indian treatise on horary astrology:

The great teachers declare that the vast science of astrology possesses six limbs:
Natal Astrology (Jataka), Observational Astronomy (Gola), Omens (Nimitta),
Inquiry (Prashna), Electional Astrology (Muhurta), and Mathematics (Ganita).

Thus, scholars recognize these six limbs—Natal Astrology and the others—within the discipline. This science has attained an even more expansive form, becoming enriched by fields such as psychology and medicine. However, upon close examination, all these considerations are ultimately contained within the original three branches.

Natal Astrology (Hora)

Scholars believe that the word Hora is derived from the word Ahoratra meaning "day and night," or a full 24-hour cycle. As stated in the Brihat Jataka The foundational text of Indian predictive astrology by Varahamihira:

Some maintain that the word 'Hora' is formed by dropping the first and last syllables
of 'Ahoratra' original: "aho-ratra" becomes "ho-ra".
It reveals the ripening of the good and evil fruits of actions
earned by an individual in their previous lives.

This branch of Hora is also known by the name Jataka Skandha (the branch of birth). In this section, the auspicious and inauspicious results that will occur in a person's life are predicted according to the positions of the planets at the time of birth. Within this branch of Hora, many topics are examined, such as: the nature of planets and zodiac signs, the consideration of colors, directional strengths, the twelve houses, the mutual aspects of planets, friendships and enmities, the system of eight-fold points (Ashtakavarga), the determination of longevity, combinations for royal success (Raja Yogas), and the major and minor planetary periods (Dashas and Antardashas).