HOW diwali dates occur in Indian calendar

Diwali is usually the Hindu festival of lights that takes place in October or November. The date of Diwali is normally set by the Hindu calendar and so it does vary with the Western calendar. It is a New Year festival in the Vikrama calendar; it falls on the night of the new moon that is in the month of Kartika.

Every year, Diwali falls on a different date since the day is calculated according to the position of the moon. According to Hindu reckoning, the date of Diwali falls on the 15th day of the dark fortnight in the auspicious Hindu month of Kartik or the month of October/November in English calendar.

Diwali is one of the most important Indian national celebrations as it also marks the beginning of a new year. Diwali dates change every year as the day is calculated according to the position of the moon.

 Hindu Calendar:

Hindu calendar is a collective name for most of the lunisolar calendars and solar calendars used in India since ancient times. Since ancient times it has undergone many changes in the process of regionalization and today there are several regional Indian Hindu calendars. It has also been standardized as Indian national calendar. Nepali calendar, Assamese Calendar, Bengali calendar, Malayalam calendar, Tamil calendar, Telugu calendar, Kannada calendar etc. are some prominent regional Hindu calendars.^[1] The common feature of all regional Hindu calendars is that the names of the twelve months are the same (because the names are based in Sanskrit) though the spelling and pronunciation have come to vary slightly from region to region over thousands of years. The month which starts the year also varies from region to region. The Buddhist calendar and the traditional lunisolar calendars of Cambodia, Laos, Myanmar, Sri Lanka and Thailand are also based on an older version of the Hindu calendar.

Most of the Hindu calendars are inherited from a system first enunciated in Vedāṅga Jyotiṣa's of Lagadha, a late BCE adjunct to the Veda-s, standardized in the Sūrya Siddhānta (3rd century CE) and subsequently reformed by astronomers such as Āryabhaṭa (499 CE), Varāhamihira (6th century CE), and Bhāskara II (12th century CE). Differences and regional variations abound in these computations, but the following is a general overview of Hindu lunisolar calendar.

YEAR Names:

Apart from the numbering system outlined above, there is also a cycle of 60 calendar year names, called Samvatsaras, which started at the first year (at elapsed years zero) and runs continuously:

1. Prabhava   2. Vibhava   3. Shukla   4. Pramoda   5. Prajāpati   6. Āngirasa   7. Shrīmukha   8. Bhāva   9. Yuva 10. Dhātri 11. Īshvara 12. Bahudhānya 13. Pramādhi 14. Vikrama (2000-2001) 15. Vrisha (2001-02) 16. Chitrabhānu (2002-03) 17. Svabhānu (2003-04) 18. Tārana (2004-05) 19. Pārthiva (2005-06) 20. Vyaya (2006-2007)

21. Sarvajeeth (2007-08) 22. Sarvadhāri (2008-09) 23. Virodhi (2009-10) 24. Vikrita (2010-11) 25. Khara (2011-12) 26. Nandana (2012-13) 27. Vijaya (2013-14) 28. Jaya 29. Manmadha 30. Durmukhi 31. Hevilambi 32. Vilambi 33. Vikāri 34. Shārvari 35. Plava 36. Shubhakruti 37. Sobhakruthi 38. Krodhi 39. Vishvāvasu 40. Parābhava

41. Plavanga 42. Kīlaka 43. Saumya 44. Sādhārana 45. Virodhikruthi 46. Paridhāvi 47. Pramādicha 48. Ānanda 49. Rākshasa 50. Anala 51. Pingala 52. Kālayukthi 53. Siddhārthi 54. Raudra 55. Durmathi 56. Dundubhi 57. Rudhirodgāri 58. Raktākshi 59. Krodhana 60. Akshaya

This system contains the concept of leap year also.Every 4th year will have 366 days and the others only 365.The starting point is Meshadi or Mesha Sankranti, ( 1st of the month Meṣa or the Hindu solar new year).It is also calculated a day by day mode.beginning from 1 presently it runs 1864000+.... days.This means these much days have passed in the present Kaliyuga (1/10 ofCatur-Yuga's total)

The time cycles in India are:

·         60-year cycle

·         Year

·         6 seasons of a year

·         about 60 days (2 months) in a season

·         Month (lunar)

·         2 pakshas in a month, shukla (waxing) and krishna (waning)

·         15 tithis in a paksha (1-14, 15th is purnima or amavasya)

·         60 ghatikas (or 30 muhurtas or 8 praharas) in a 24-hour period (ahoratra).

·         30 Kala (approx) in 1 muhurta

·         30 Kastha in 1 kala

·         15 Nimisha in 1 kastha

Years are synchronized with the solar sidereal year by adding a month every three years. The extra month is termed as "Adhik Mass" (extra month). This extra month is called Mala Masa (impure month) in Eastern India.

DATE conversions:

Converting a date from an Indian calendar to the common era can require a complex computation. To obtain the approximate year in the common era (CE):

·         Chaitradi Vikram (past) : Chaitra-Pausha: subtract 57; Pausha-Phalguna: subtract 56.

·         Shaka: add 78-79

·         Kalachuri: add 248-249

·         Gupta/Valabhi: add 319-320

·         Bangla: add 593-594

·         Vira Nirvana Samvat: subtract 527-526

·         Yudhishthira Samvat: Subtract 3101 (Ascension of Lord Krishna at age 125) from common era

·         Sri Krishna Samvat: Subtract 3226 (Birth of Lord Sri Krishna) from common era

·         Balabhi Samvat: add 320 to common era