The annual solar clock · twelve crossings
See the saṅkrāntis in action
Let Earth travel around the Sun, then watch that same moment from an Earth-centered measuring view. Each time the apparent Sun enters the next 30-degree sidereal rāśi, a new saṅkrānti occurs.
Two synchronized views
Watch a physical orbit become a calendar measurement.
Play the loop, change its speed, drag the apparent Sun, or choose any rāśi boundary. The animation celebrates each crossing long enough for you to see the new saṅkrānti name.
The apparent Sun has just crossed from Dhanus into Makara.
Boundary crossing: the apparent Sun crossed from Dhanus into Makara.
What “projection” means here
The zodiac ring is a coordinate-measuring framework.
Earth really orbits the Sun. From Earth, however, the Sun appears to move against the background sky during the year. Extend the Earth-to-Sun sightline to the ecliptic—the Sun's apparent yearly path—and the direction receives a zodiac longitude. The animation's right-hand ring displays that Earth-centered measurement.
Twelve equal 30-degree divisions make 360 degrees. A saṅkrānti is the instant that the apparent Sun's sidereal longitude reaches the beginning of the next division.
Where the first boundary begins
A named ayanāṃśa places the sidereal zodiac on the sky.
This teaching model makes all twelve divisions equal and easy to see. A real calculation must also name the ayanāṃśa convention that locates sidereal 0°. Open Pañcāṅga's live solar checks use its documented Lahiri (Citrāpakṣa) approximation.