🪷 ज्येष्ठ पूर्णिमा · Jyeṣṭha Pūrṇimā (Vaṭa Sāvitrī)

Tradition

Tradition: Pan-Hindu

Vrata: Yes (fasting day)

How the day is decided

The Pūrṇimā, caturdaśī-viddhā, holding three muhūrtas or more before sunset: that day; with less, the next (the author adds: for the pūjā-only vrata with an eighteen-nāḍī caturdaśī, the next).

Source: Dharmasindhu, Vaṭa-sāvitrī (OCR 2927-2942). Computed on the Sūrya Siddhānta's sunrise, tithi and Moon at Ujjayinī (a city's page uses that city's sunrise).

Detection Rule (Pure Pañchāṅga-Based)

{
  "tithi_number": 15,
  "tithi_paksha": "Śukla",
  "lunar_month": "Jyeṣṭha",
  "kala_rule": "vat-savitri"
}