The position of Adhik Maas amongst the other months is variable, re-occurring about every 32.5 months. This is in contrast to some other common lunisolar calendars that insert an intercalary lunar month at a fixed point of the year. For example, in the Jewish calendar, the extra month is added before Adar; in the Buddhist calendar, it is added after Ashadha / Waso.
During 2018, Adhik Jyestha (extra month after Jyestha) was observed from 16 May to 13 June. In 2020, Adhik Ashwin (extra month after Ashwin) will be from 18 September to 16 October 2020, leading to an unusual month long break between Pitri Paksha and Durgā Pujā / Navarātri.
The other names for Adhik Maas is Mal Maas. Spellings in the Latin alphabet vary, includingadhik, adhika; mal, mala; maas, maasa, mās, māsa, mas. This is the thirteenth month of the lunar calendar. Adhik Maas adopts the name of the month that follows. It is a time for prayer, fasting, charity, and self-improvement.[clarification needed]
The concept of Adhik Maas is one of the most accurate methods to adjust the gap between Solar and Lunar Year.
When the Sun does not at all transit into a new rāshi (30° sidereal zodiac) but simply keeps moving within a rāshi in a lunar month (i.e. before a new moon), then that lunar month will be named according to the first upcoming transit. It will also take the epithet adhik or "extra". The transition of the sun from one rāśi to the next is called sankranti. For example, if a lunar month elapsed without a sankranti and the next transit is into Mesha (Aries), then this month without transit is labelled Adhik Chaitra. The next month will be labeled according to its transit as usual and will get the epithet nija ("original") or shuddha ("clean"), in this case Nija Chaitra. The terms Pratham (first) Chaitra and Dwitiya (second) Chaitra may also be used.
Extra Month, or Adhika Māsa falls every 32.5 months on an average. The solar year is made up of 365 days and about 6 hours, and the lunar year is made up of 354 days. Thus there is a gap of 11 days, 1 hour, 31 minutes and 12 seconds between the lunar and the solar years. As this gap accumulates each year, it approximates in 2.7 years to one month. No adhik mas falls during Margsheersh to Magh. A case of Adhik Karttik is extremely rare, but in the 250-year span (1901-2150 AD) it would occur once, in 1963 AD.
The Moon takes about 27.3 days to make one complete orbit around the earth. The earth orbits around the sun once every 365.2422 days (= earth's orbital speed of 29.79 km per second). The earth and the moon in 27.3 days have moved as a system about 1/12 of the way around the sun. This means that from one full moon to the next full moon, the moon must travel 2.2 extra days before it appears again as a full moon, due to the curve of the earth's orbit around the sun. Ultimately this creates a variance of 10.87 days a year between a lunar year and a solar year. To compensate for this difference, the additional month is added after every 32.5 months on average.
Advance Ephemeris by N. C. Lahiri contains the full list of all Adhik and Kshaya months during 1913-2016 AD by both modern astronomy and Surya Siddhanta on page 92.
Religious significance of Adhik Maas
A month-long mela (fair) is celebrated in Machhegaun village in Nepal during Adhika Māsa. It is general belief that one can wash away all his sins by taking a bath in the pond at Machhenarayan temple.
Since this is a special month which does not come every year, there are no specific festivals like Dussehra or Diwali in this month. Rather this month is treated as special and holy month and many people perform the adhik maas vrata. People perform extra mala japas, pradakshinas, pilgrimages, scriptural reading and parayanas.
During Adhik Maas, people perform various types of religious rituals such as keeping fast, recitation of religious scriptures, mantras, prayers, performing various types of puja and havan. Vratas (fasts) of various durations (full day, half day, weekly, fortnight, full month) are often undertaken. The vratas may be of complete fasting with liquids only or without liquids, fasting with fruits only or keeping fast with vegetarian food, as the individual can tolerate. It is said that the persons performing good deeds (satkarma) in this month conquer their senses (indriyas) and they totally come out of punar janam (the cycle of rebirth).
In Beed district of Maharashtra there is a small village (with population 659 of whom 54.6 % belong to Scheduled Casted) called Purushottampuri where there is Temple of God Purushottam. Every Adhik Mass there is big fair and thousands of people come from various places to take the blessings of God Purushottam. This is the only temple dedicated to God Purushottam. Moreover, this is the only temple where people come to worship during Adhik Maas, due to which a false idea has evolved during recent decades that Adhik Maas is Purushottam Maas. Like eclipses, Adhil Maas is inauspicious for Hindus and no auspicious events like marriage, upanayana,etc can he held during Adhik Maas. In order to alleviate the inauspiciousness, people perform austerities, worships, japa, etc during such inauspicious times. In Gita, Purushottam Maas is used for Agrahaayana luni-solar month after the name of Lord Krishna. Varahamihira's Pancha-Siddhantika <ref> contains the extant Vasishtha Siddhanta which has no reference to the word "Purushottam". Original Vasishtha Siddhanta was lost thousands of years ago, even Varahamihira's Pancha-Siddhantika could mention only a handful of references from Vasishtha Siddhanta.
- Hindu Chronology, Encyclopædia Britannica Eleventh Edition (1911)
- The Astronomical Basis of the Hindu Lunisolar Calendar
- Hindu Calendars in various Indian Languages
- Hindu Calendars 2020
- Adhik Maas 2020