Jyotish

Jyotish, the "science of light", is the astrology that grew up in India and was taught in Sanskrit; in English it is also called Vedic astrology. A Jyotishi is someone who practises it. It reads a person's life from the sky at the moment of their birth: where each graha (planet) stood, as seen from the Earth.

Why the moment of birth matters

The astrology of newspaper columns sorts people by the Sun's sign alone, which changes once a month: everyone born in the same few weeks gets the same reading. Twins are the hard case for that. They arrive on the same day, in the same town, often within the same hour, and still many of them turn out unlike each other in character and in what happens to them. An astrology worth taking seriously has to be able to tell twins apart.

Jyotish tries to meet that demand by looking at far more than the Sun. Besides where each graha stands among the twelve rasis (signs) and the twenty-seven nakshatras (constellations), it uses the lagna (ascendant), the point of the zodiac rising on the eastern horizon. The lagna passes through every rasi in about a day, so it moves much faster than any graha, and everything counted from it moves with it: the twelve bhavas (houses), and the finer charts built by dividing each rasi into smaller parts. In the charts of twins born a few minutes apart the slow parts agree while the fast ones may not, and Jyotish reads both.

The book behind hora

hora follows one book, P.V.R. Narasimha Rao's Vedic Astrology: An Integrated Approach. Its rules decide how hora calculates, and its order decides the order of these pages, which explain each concept in our own words; the book itself is where the full teaching is. Each page names the chapter and section it belongs to.

How to use hora

1. On the home page, enter the birth data: the date and time of birth, the UTC offset (stated, or worked out from the birth place for local mean or apparent time), and the latitude and longitude of the birth place. The other choices have sensible defaults; change them only if you know you need to.
2. Choose Calculate the chart. hora shows the rasi chart drawn in the style you chose, a table with each graha's rasi, degree, bhava and nakshatra, and the panchaanga, the five limbs of the moment of birth.
3. To understand what you see, read the knowledge base. Its pages follow the book's order, starting with this one; next comes the graha.

Book reference: P.V.R. Narasimha Rao, Vedic Astrology: An Integrated Approach, chapter 1, § 1.1–1.2. Where to get the book