Nadi Amsa & Nadi Astrology
Nadi Astrology is based on Nadi Amsa, which is 150 division of a Rashi. The divisions are equal as per Chandra Kala Nadi book. But modern astrologers use unequal division which is logical, mathematical and scientific. In unequal division all the 16 vargas fall in place in each Rashi.
On a space-time-scale a nadi is equal 12 min of an arc with 48 sec. Each birth or event is separated by this nadi and makes it unique. That way even if two births have the same lagna, the Nadi-lagna will be different, making the birth unique. This is true for twin or multiple births of the same womb.
Nadi Astrology is based on this Nadi Amsa.
Ascertaining the Nadi Lagna is tricky, but Sage Agasthya had given a simple way to delineate. I use this lagna to predict and time accurately events.