Settings How every page on this site computes: the ayanamsa, the house system, the lunar nodes, which sunrise and which Tamil reckoning, and how the charts are drawn. Kept on this device.

The ayanamsa moves every sidereal degree on the site — every sign, star, pada, dasha date and muhurtham window follows it. The house system changes only house placements: which house a graha is counted in, never its sign or star.

Everything is at the almanac defaults.

Ayanamsa#

Where the sidereal zodiac begins. The value beside each is today’s.

Ayanamsa Lahiri (Chitrapaksha)24°13′58″ The ayanamsa of the Indian Calendar Reform Committee (1955) and the Rashtriya Panchang, printed in most Tamil and North Indian almanacs. Raman22°47′11″ B. V. Raman’s ayanamsa, used by readers of his Astrological Magazine, his ephemerides and his textbooks. KP (Krishnamurti)24°08′09″ K. S. Krishnamurti’s ayanamsa, the one Krishnamurti Paddhati reads its cusps and sub lords in. True Chitrapaksha24°12′41″ Holds Chitra (Spica) at exactly 180° from the star’s apparent place, for astrologers and software such as Jagannatha Hora that keep the Lahiri principle to the arcsecond. Pushya-paksha23°05′40″ Holds Pushya (δ Cancri) at 16° Kadagam; used by some Kerala and Tamil astrologers and advocated by P. V. R. Narasimha Rao. Sri Yukteshwar22°51′16″ From Sri Yukteswar Giri’s The Holy Science (1894), used by followers of his yuga reckoning. Fagan–Bradley25°06′58″ The standard of Western sidereal astrology, from Cyril Fagan and Donald Bradley, used in Western sidereal ephemerides. Sassanian20°22′07″ Zero in 564 CE, the epoch of the Persian Zij-i Shah, used when reading Persian and early Arabic horoscopes. Custom24°13′58″ Your own value at 1 January 2000, carried forward by precession, to match an almanac or program not listed here.

Custom ayanamsa on 1 January 2000, in degrees

23°51′25″ in 2000, 24°13′58″ today. Lahiri’s is 23.8565. Choose Custom above to use it.

Houses#

Which house a graha is counted in. Signs, stars and the drawn rasi chart stay as they are.

House system Whole sign (rasi chart)default Each sign is one house, counted from the lagna’s sign: the rasi chart every Tamil almanac draws, and what the dosha and porutham rules count by. Sripati (bhava chalit) The lagna and the meridian cut the sky into four quadrants, each trisected; the cusps are bhava middles, the bhava chart printed beside the rasi chart. Equal from the lagna Twelve houses of exactly 30°, the first beginning at the lagna degree. Porphyry The same trisected quadrants as Sripati, with each cusp taken as the start of its house, as Western Porphyry charts do. Placidus Quadrants divided by the time each degree takes to rise and culminate; the common Western system and the one KP uses.

Wherever a page reads a graha’s house from its chart — the jathagam tables, the dosha checks, the yogas — it takes it from the system chosen here.

Rahu and Ketu#

Which lunar node the charts use.

Lunar nodes Mean nodedefault The smoothed average of the Moon’s node, which always moves backwards: the Rahu and Ketu that almanacs and most jathagams print. True node The node of the Moon’s actual orbit at the moment, which swings up to about 1.6° either side of the mean and now and then stands still or moves forward.

Sunrise#

Almanacs differ on what counts as sunrise, by three to four minutes in Tamil Nadu.

Which part of the Sun Upper limbdefault Sunrise is the first gleam of the Sun’s upper edge: the Rashtriya Panchang, the Indian Astronomical Ephemeris and most modern almanacs. Centre of the disc Sunrise is the moment the Sun’s centre reaches the horizon, the Surya Siddhanta’s definition, which some Tamil almanacs still print.

Allow for refraction — the air lifts the Sun about 34′, so it is seen before it is geometrically up. Off, as the Surya Siddhanta reckons it.

Everything that counts from sunrise follows this choice: the panchangam and the calendars, the muhurtham windows, Rahu kaal and Gulika kaal, and the chart values that start from sunrise.

Tamil month#

Which Sun the Tamil calendar is reckoned from. Most printed Tamil calendars are vakya; astronomical ones are thirukanitha, and the two can differ by a day.

Reckoning Thirukanitha The Sun as it actually stands: the reckoning Drik Panchang, Prokerala and the Chennai daily calendars print. Vakyadefault The classical Sun of the Pambu panchangam, which most printed Tamil wall calendars follow. It runs behind the true Sun, so a month can begin a day later.

The Tamil month begins when the Sun enters a sign before sunset, and the two reckonings put that instant a few hours apart — enough to move the first of the month by a day about a third of the time. Only the Tamil calendar follows this: the Malayalam, Telugu, Kannada and north Indian calendars keep the astronomical Sun.

Charts#

How the rasi and navamsa charts are drawn on every page.

South Indian: the signs stay in place and the lagna is marked where it falls, as Tamil almanacs draw it.