Tula Sankranti on Oct 17: why it comes 24 days after the September equinox

The Sun enters the sidereal sign of Tula (Libra) on the evening of Saturday, October 17, 2026, marking Tula Sankranti, the start of the solar month of Kartika in the Hindu solar calendar. Most published panchang calculations place the moment of transit at about 7:50 pm Indian Standard Time, with figures ranging from 7:48 pm to 7:57 pm depending on the calculation used. The day is also known as Garbhana Sankranti in Odisha, where Goddess Lakshmi is worshipped with fresh rice, wheat grains and branches of the kara plant, and as Tula Sankramana in Karnataka, where it is linked to the Kaveri river. Panchang makers describe Tula Sankranti as the sidereal counterpart of the autumn equinox, which this year fell nearly four weeks earlier, on September 23.

Indian solar calendars count months by the Sun's entry into each of the twelve signs measured against the fixed stars. This is the sidereal zodiac. Western astronomy and most of the world's calendars measure the Sun's position from the equinox point instead, which is the tropical system. The two systems once lined up, but the equinox point slides slowly backwards through the stars because the Earth's axis wobbles like a spinning top. This motion is called the precession of the equinoxes.

The result can be seen on today's date. In the tropical system the Sun enters Libra at the September equinox. In the sidereal system it enters Tula only when it reaches the stars that mark the sign's start. Under the Lahiri convention, recommended by the Calendar Reform Committee headed by Meghnad Saha and adopted by the Government of India in 1953, that starting point is fixed so that the bright star Spica, called Chitra in Indian astronomy, sits at the beginning of Libra.

The numbers can be checked with simple arithmetic. The Sun moves about 0.986 degrees a day along its path. From 5:35 am on September 23 to about 7:50 pm on October 17 is roughly 24.6 days, which gives about 24.2 degrees. That matches the 2026 ayanamsa of about 24 degrees 13 minutes, or 24.2 degrees, published in sidereal ephemeris tables. In other words, the date of Tula Sankranti is the equinox shifted by the accumulated precession.

This is why Indian Sankrantis drift slowly later against the Gregorian calendar over very long periods. The calendar committee's work is still carried on by the Positional Astronomy Centre of the India Meteorological Department in Kolkata, which publishes the Indian Ephemeris and the Rashtriya Panchang. The story is also a reminder that the traditional calendar rests on careful observation and calculation, not only on custom.

Short-term: Families following the solar calendar mark the new month of Kartika, observe the punya kaal, the window panchangs give for charity and rituals on the day, and in Odisha and Karnataka take part in Garbhana Sankranti and Tula Sankramana observances.

Long-term: Because precession continues, the ayanamsa will keep growing, and Sankranti dates will keep moving slowly later in the Gregorian year, by about one day every 70-odd years.

Who is affected: People who follow Hindu solar calendars and festival dates, students of Indian astronomy, and anyone curious about why Indian and Western sign dates differ.

Questions and Answers