The Raman ayanamsa
The Raman ayanamsa was proposed by B. V. Raman, an astrologer and writer, and is used in some South Indian and Western-influenced Vedic practice. On this site its base value at J2000 is 22.4108 degrees, about 1.45 degrees less than Lahiri.
Origin
B. V. Raman (1912–1998) developed and popularised this ayanamsa in his books and his journal, the Astrological Magazine. It is one of several conventions proposed in the 20th century to set the sidereal zero point.
Value and use
The base value at J2000 is 22.4108 degrees, with the same yearly drift as the other ayanamsas on this site. Choosing Raman moves every planet about 1.45 degrees forward compared with Lahiri, which can change the sign or nakshatra of a planet near a boundary.
When to choose it
Use Raman if your teacher, book or almanac follows it. Compare the result with Lahiri: if a planet falls near a sign or nakshatra edge, the two ayanamsas can give different answers, and both are valid conventions.
Verification status
The base value is taken from the same source as the other ayanamsas on the method page. It has not yet been checked against a published Raman-based almanac; this is pending.
Setting it side by side with Lahiri
The Raman ayanamsa sits about 1 degree and 45 minutes below Lahiri at J2000. For a planet in the middle of a sign, the difference changes nothing. A planet within about two degrees of a sign boundary can change sign, and a planet within a similar distance of a nakshatra boundary can change nakshatra. A quick test is to compute a chart with both values and list the planets whose signs differ. For most charts the list is short. Where it is long, the reader should be cautious about any reading that depends on exact signs, and should say which ayanamsa the reading assumes.
Who uses it and why
Raman's ayanamsa is associated with the astrologer B. V. Raman, whose books and journal were widely read in the twentieth century. Some readers and practitioners adopt it because their teacher or their favourite text uses it. Others prefer it because the resulting chart matches a published almanac they trust. Neither reason makes the calculation more or less correct. The method is consistent, and the choice is a matter of tradition. Before using Raman, check which edition of the almanac or which text you follow, since the values in print can differ slightly.
How to read a result that depends on it
When a reading depends on a sign that changes between Lahiri and Raman, the honest course is to present both results with their causes. Say that the planet is in one sign under one convention and in the neighbouring sign under the other, and then say which of the two the reading follows. This is more useful to the reader than a single confident statement, and it leaves the decision with the person who has the full picture. The same approach works for any ayanamsa: the result is a fact about the convention, and the reading is a judgement that should be stated as such.