Hinduism

=== Calendar ===
{{See also|Astronomical basis of the Hindu calendar}}
{{Main|Hindu calendar}}
The Hindu calendar, Panchanga ({{Lang-sa|पञ्चाङ्ग}}) or Panjika is one of various [[lunisolar calendar]]s that are traditionally used in the [[Indian subcontinent]] and [[Southeast Asia]], with further regional variations for social and [[Hindu]] religious purposes. They adopt a similar underlying concept for timekeeping based on [[sidereal year]] for solar cycle and adjustment of lunar cycles in every three years, but differ in their relative emphasis to moon cycle or the sun cycle and the names of months and when they consider the New Year to start.<ref name="richmond80">{{Cite book |author=B. Richmond |url=https://books.google.com/books?id=wwEVAAAAIAAJ |title=Time Measurement and Calendar Construction |publisher=Brill Archive |year=1956 |pages=80–82 |access-date=18 September 2011 |archive-date=28 March 2024 |archive-url=https://web.archive.org/web/20240328165207/https://books.google.com/books?id=wwEVAAAAIAAJ |url-status=live }}</ref> Of the various regional calendars, the most studied and known Hindu calendars are the [[Shaka era|Shalivahana Shaka]] (Based on the [[Shalivahana|King Shalivahana]], also the [[Indian national calendar]]) found in the [[Deccan Plateau|Deccan region]] of Southern India and the [[Vikram Samvat]] (Bikrami) found in Nepal and the North and Central regions of [[India]] – both of which emphasise the lunar cycle. Their new year starts in spring. In regions such as Tamil Nadu and Kerala, the solar cycle is emphasised and this is called the [[Tamil calendar]] (though Tamil calendar uses month names like in Hindu Calendar) and [[Malayalam calendar]] and these have origins in the second half of the 1st millennium CE.<ref name="richmond80" /><ref name="Fuller2004p109">{{cite book |author=Christopher John Fuller |url=https://books.google.com/books?id=To6XSeBUW3oC |title=The Camphor Flame: Popular Hinduism and Society in India |publisher=Princeton University Press |year=2004 |isbn=978-0-69112-04-85 |pages=109–110 |access-date=10 July 2016 |archive-date=28 March 2024 |archive-url=https://web.archive.org/web/20240328162536/https://books.google.com/books?id=To6XSeBUW3oC |url-status=live }}</ref> A Hindu calendar is sometimes referred to as [[Panchangam]] (पञ्चाङ्गम्), which is also known as [[Panjika]] in Eastern India.<ref>{{cite book |author=Klaus K. Klostermaier |url=https://books.google.com/books?id=E_6-JbUiHB4C&pg=PA490 |title=A Survey of Hinduism: Third Edition |publisher=State University of New York Press |year=2007 |isbn=978-0-7914-7082-4 |page=490 |access-date=10 June 2023 |archive-date=28 March 2024 |archive-url=https://web.archive.org/web/20240328161801/https://books.google.co.in/books?id=E_6-JbUiHB4C&pg=PA490&redir_esc=y#v=onepage&q&f=false |url-status=live }}</ref>

The ancient Hindu calendar conceptual design is also found in the [[Hebrew calendar]], the [[Chinese calendar]], and the [[Babylonian calendar]], but different from the Gregorian calendar.<ref name="nesbittbc">{{cite book |author=Eleanor Nesbitt |url=https://books.google.com/books?id=XebnCwAAQBAJ&pg=PA122 |title=Sikhism: a Very Short Introduction |publisher=Oxford University Press |year=2016 |isbn=978-0-19-874557-0 |pages=122–123 |access-date=10 June 2023 |archive-date=15 April 2023 |archive-url=https://web.archive.org/web/20230415073742/https://books.google.com/books?id=XebnCwAAQBAJ&pg=PA122 |url-status=live }}</ref> Unlike the Gregorian calendar which adds additional days to the month to adjust for the mismatch between twelve lunar cycles (354 lunar days)<ref>{{cite book |author=Orazio Marucchi |url=https://books.google.com/books?id=PoBjBYdzrkQC&pg=PA289 |title=Christian Epigraphy: An Elementary Treatise with a Collection of Ancient Christian Inscriptions Mainly of Roman Origin |publisher=Cambridge University Press |year=2011 |isbn=978-0-521-23594-5 |page=289}}, Quote: "the lunar year consists of 354 days".</ref> and nearly 365 solar days, the Hindu calendar maintains the integrity of the lunar month, but inserts an extra full month, once every 32–33 months, to ensure that the festivals and crop-related rituals fall in the appropriate season.<ref name="nesbittbc" /><ref name="Fuller2004p109" />

The Hindu calendars have been in use in the Indian subcontinent since Vedic times, and remain in use by the [[Hindu]]s all over the world, particularly to set Hindu festival dates. Early Buddhist communities of India adopted the ancient Vedic calendar, later Vikrami calendar and then local [[Buddhist calendar]]s. Buddhist festivals continue to be scheduled according to a lunar system.<ref>{{cite book |author=Anita Ganeri |url=https://books.google.com/books?id=B-EawToG-6YC&pg=PT11 |title=Buddhist Festivals Through the Year |publisher=BRB |year=2003 |isbn=978-1-58340-375-4 |pages=11–12}}</ref> 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. Similarly, the ancient [[Jain]] traditions have followed the same lunisolar system as the Hindu calendar for festivals, texts and inscriptions. However, the Buddhist and Jain timekeeping systems have attempted to use the Buddha and the Mahavira's lifetimes as their reference points.{{Sfn|Long|2013|pp=6–7}}<ref>{{cite book |author=John E. Cort |url=https://books.google.com/books?id=Ip7mCwAAQBAJ&pg=PA142 |title=Jains in the World: Religious Values and Ideology in India |publisher=Oxford University Press |year=2001 |isbn=978-0-19-513234-2 |pages=142–146}}</ref><ref>{{cite book |author1=Robert E. Buswell Jr. |url=https://books.google.com/books?id=DXN2AAAAQBAJ&pg=PA156 |title=The Princeton Dictionary of Buddhism |author2=Donald S. Lopez Jr. |publisher=Princeton University Press |year=2013 |isbn=978-1-4008-4805-8 |page=156}}</ref>

The Hindu calendar is also important to the practice of Hindu astrology and zodiac system. It is also employed for observing the auspicious days of deities and occasions of fasting, such as [[Ekadashi]].<ref>{{cite web |date=22 May 2017 |title=Ekadasi: Why Ekadasi is celebrated in Hinduism?-by Dr Bharti Raizada |url=https://www.newsgram.com/ekadasi-importance-hinduism/ |website=NewsGram }}{{Dead link|date=June 2023 |bot=InternetArchiveBot |fix-attempted=yes }}</ref>