Saṅkrānti · the Sun · twelve solar landmarks
Meet the twelve saṅkrāntis
Saṅkrānti means a passage or transition. In this calendar setting it is the calculated instant when the Sun enters the next sidereal rāśi, or zodiac sign. There are twelve such crossings in a solar year.
See the saṅkrāntis in actionMove the Sun through all twelve sidereal sign crossings.→
A different calendar clock
A tithi follows the Moon–Sun angle; a saṅkrānti follows the Sun.
The lunar side of a pañcāṅga divides the changing angle between the Moon and Sun into thirty tithis. The solar side follows the Sun's apparent annual path through twelve equal 30-degree regions of the sky.
Each boundary crossing is a saṅkrānti. The crossing into Makara is Makara Saṅkrānti; the crossing into Meṣa is Meṣa Saṅkrānti, and so on.
The twelve rāśis
The entered sign gives each monthly landmark its name.
Aries
Taurus
Gemini
Cancer
Leo
Virgo
Libra
Scorpio
Sagittarius
Capricorn
Aquarius
Pisces
Rāśi means a group or division and is the Sanskrit calendar term used here for one of these twelve sidereal signs.
How the boundary is placed
A named ayanāṃśa connects the observed longitude with the sidereal signs.
NASA/JPL Horizons supplies an apparent geocentric longitude for the Sun. Open Pañcāṅga then applies its documented Lahiri (Citrāpakṣa) ayanāṃśa approximation to place the starting point of the sidereal zodiac. A crossing occurs when the resulting sidereal longitude reaches the next multiple of 30°.
Another documented ayanāṃśa can place a boundary a little differently, so a saṅkrānti near local midnight may be assigned to a neighboring civil date by another calendar.
Science first: protect your eyes
Explore the solar calendar with diagrams and calculations.
The sunglasses in our illustration are a playful sign that this is a bright daytime adventure. Certified solar-viewing protection is essential for direct viewing. Ordinary sunglasses cannot protect your eyes. Never look directly at the Sun or through a camera, telescope, or binoculars without correctly fitted equipment made specifically for safe solar viewing.
The explorers study a model rather than the Sun itself. Their golden marker crosses from one of twelve sky divisions into the next—the passage named saṅkrānti.
Safety guide: NASA Science, safe solar viewing
Landmark first, observance second
Each saṅkrānti is a calendar landmark with its own meanings.
The daily report can identify the entered rāśi without assigning one universal festival, deity, vrata, pūjā, or regional practice to every crossing. A named observance appears only when its own reviewed rule matches.
Open reference: National Mission for Manuscripts, Somasiddhānta