Article text is currently English only. The calculation below and the rest of the interface follow your chosen language.
In short
The Ascendant is the exact degree of the zodiac rising on the eastern horizon at the moment and place of birth; its sign is the Lagna. This app computes it from the birth instant, latitude and longitude, then shifts it onto the sidereal zodiac. It moves about a degree every few minutes, so it is the most time-sensitive point in a chart.
What the term means
The Ascendant is a degree, not a sign: the point of the zodiac crossing the eastern horizon at the birth moment, seen from the birth place. Its sign is the Lagna. English translations often use the two words for the same thing; Saravali's translation renders Lagna as "Ascendant" throughout. On this site "Ascendant" usually means the exact degree, and the Lagna the sign that holds it.
Where the term comes from
BPHS Ch. 3 Sl. 4-6 calls the rising rashi the Lagna. The translator's addition explains the astronomy: it is the sign rising in the east on the latitude of birth, the apparent rising caused by the earth's rotation. A rashi takes roughly two hours to cross the horizon, so a degree takes about four minutes, but the real duration depends on the latitude.
How this app computes it
- Local sidereal time is Greenwich sidereal time plus the birth longitude. With the tilt of the ecliptic and the birth latitude, that gives the rising degree on the tropical zodiac; the Lahiri ayanamsa is then subtracted.
- For 19 January 1985, 11:14 IST, New Delhi, the tropical rising degree is 16.68 degrees (Aries); less an ayanamsa of 23.64 degrees, that is 353.04 sidereal, Pisces 23.04, in Revati.
- Four minutes earlier it is Pisces 21.64, four minutes later Pisces 24.43: about 1.4 degrees each way here, not exactly the one degree of the rule of thumb. By 11:44 it has crossed into Aries.
- The project's checks require the Ascendant at local sunrise to sit just behind the Sun's longitude, within 1.5 degrees, and to sweep the full circle in a day.
- It is computed only with a birth time and a resolved place, and its sub-lord is shown only when the place resolved.
Pages that use this term
- Nakshatra sub-lord and birth time - how far a few minutes move the Ascendant's sub-lord.
- When the birth time is unknown - what the chart can say without it.
- The 1st house (Tanu Bhava) - the house the Ascendant's sign becomes.
- Lagna calculator - the rising degree and sign for a birth.
- Methodology - one Ascendant worked through and checked against sunrise.
Related terms
- Birth-time rectification - working back to a time, which this app does not do.
- Longitude - both the birth place's and the rising degree's.
- Cusp - the Ascendant is not used as one here.
- Pada - the quarter-nakshatra the Ascendant crosses in minutes.
Lagna (Ascendant)
The rising sign and degree, and the twelve whole-sign houses counted from it.
What it needs
Date, time and place
That is more than this article asks for - it only ever takes a date, and sometimes a time, and never a name or a birth place. So this one runs on its own page, which asks for exactly what it needs and stores none of it.
Run it on its own page