nadi jyotish(nāḍi jyotiṣa) in Hindu astrology?
How much the predictions exactly true?
Does anyone have any idea about that temple's name ?
nadi jyotishis different from
The Temple town : The name of the temple town, famous for Nadi Astrology in South India, is Vaitheeswaran Kovil, in Tamilnadu State. Note that, the temple itself has no connection with the numerous Nadi reading centres in the town. Even inside the town, there are some which are more costly than others, more genuine than others. And there are different Nadis' such as Shuka Nadi, Agastya Nadi and so on, named after the various rishis or sidda purushas.
What is Nadi astrology : For what is nadi jyotish, the Wikipedia page on Nadi Astrology is as good a starting place as any.
In short, it is a branch of astrology where predictions are pre-cast in the Nadi texts, and based on your precise birth time, if predictions are available and pre-written for you, they can be read for you.
Veracity of claims :
As to the truth of the predictions, the opinions are mixed. It would be best to go by personal references. Anecdotal evidence for accurate predictions, semi-accurate predictions (only about the past) and totally misplaced predictions are all common. It must also be noted that for some, the predictions might just not be available at all, that is, they were never written or not available since the ages. It requires a precise birth time to be stated to the reader.
How different from regular astrology : Kundli is regular traditional astrology that is based on the the positions of the planets in your planetary chart. Nadi is a totally different stream of astrology where the reader himself has little scope for the predicting act, except for reading what is already there and to explain the possibilities if you don't understand, and to narrow down the right chart for you based on successive queries to you about your birth time etc.