The beginning and end note of all rāgas is called sam meaning uniform and this fundamental note at present is the shadaj or ‘sa’.
Interestingly of these twenty two shrutīs in the Indian music system, only one name röhinī is common with the names of the lunar constellations. For the musical notes this name is in the division of the musical note dhaivat and is five shrutīs prior to shadaj. For the lunar constellations, röhinī is in Taurus and it was the vernal or spring equinox five to six thousand years back. (At present, the vernal equinox is in Pisces and will be moving into Aquarius around 2600 AD).This shift is due to the precession of the Earth in its orbit around the Sun and this circling takes about 26000 years to complete. Thus approx. every 1000 years the zodiac shifts by one lunar-sign. (It takes approx. 2200 years to shift by one Sun-sign). In Indian classical music the fundamental note too is shifted accordingly. Six thousand years earlier the fundamental note was five shrutīs earlier in dhaivat. In fact the name ‘shadaj’ itself means ‘born of the sixth’ . Thus every 1000 years or so, the traditional vocal music gharānās or families are to correct the fundamental note of the rāgas by one shrutī to compensate for the precession of the Earth. This is another amazing terrestrial rhythm programmed into the Dhwani system thus finely attuning it to our daily life.