What does Sankranti mean?
Sankranti is the moment the Sun enters the next zodiac sign, or rashi; in this traditional count, the boundary starts another solar month.
STEP 1
Count the sign entries
The zodiac has twelve signs of 30° each. In one full circuit, the Sun enters a new sign twelve times. To identify an entry, first check which zodiac convention the calendar uses.
STEP 2
Work an example
At 29°59′ Pisces (Meena), the Sun is one arcminute short of Aries (Mesha). At 0° Aries, Mesha Sankranti begins. The total longitude moves from 359°59′ to 360°, which wraps to 0°. The exact boundary belongs to Aries; the arcminute measures an angle, not one minute on the clock.
STEP 3
Check sidereal or tropical
A nirayana panchang uses sidereal sign boundaries. The December solstice is defined at 270° tropical, or sayana, longitude. These conventions use different starting points today, so modern Makara (Capricorn) Sankranti and the December solstice are not interchangeable calendar dates.
STEP 4
Read the published time
Subtract the Sun's degree within its sign from 30° to find the angle remaining before the next entry. For the clock time, consult that year's calendar and check its time zone and zodiac convention. Use the published entry time rather than assuming the same annual date.