The Astrological aspect of Kumbh is related with traversing planets and stars and their certain alignment . As per the Vedas the Sun is considered as a soul like or life giving. The moon is considered as a lord of Mind. The planet Jupiter or Brihaspati is consider as Guru of Gods. As it takes almost 12 years for Jupiter to transverse to complete zodiac , so the Kumbh is celebrated in accordance at one place after about every twelve years.
When Jupiter enters in Aquarius or Kumbh ( zodiac sign) and Sun and Moon in Aries and Sagittarius respectively ,Kumbh is held at Haridwar.
When the Jupiter is in Taurus or Vrishabha (zodiac sign) and the Sun and Moon are in Capricorn or Makra, the kumbha is held at Prayag.
When the Jupiter enters in Leo or Simha (zodiac sign) and the Sun and Moon in Cancer, the Kumbha is held at Nashik and Trimbakeshwar.
When Jupiter is in Leo and the Sun and Moon in Aries, the Kumbha is held at Ujjain.
Since Jupiter is in zodiac Simha the Kumbh is held at Trimbakeshwar and Nashik and Ujjain , it is known as Simhastha Kumbh.