Understanding the Concept of Adhikamasa

An Adhikamasa or inter-calary month occurs once in slightly over two years in the lunar calendar. Occurrence of any Adhikamasa can be identified, at a glance, if no Samkramana or solar ingress takes place in a lunar month. That is to say that if two New Moons occur in a single solar month, the first lunar month occurring will become automatically an Adhikamasa. In all such cases, it can be noticed that the solar ingress, which determines that particular Soura or solar month takes place just before the first New Moon of the month. Subsequently, before the next ingress of the Sun determining the next Soura month, another New Moon would have occurred and that will naturally determine the next lunar month. The first lunar month of the Soura month will be taken as an Adhikamasa and the second, as a Nijamasa. The Adhikamasa is also called Malamasa or polluted month and the Nijamasa as Suddhamasa or pure month.
According to Chaitra Paksha Ayanamsa, during the last Manmatha year, we had an Adhika Ashada month commencing on 16th June 2015 just after the end of the Jyeshta Amavasya at 19h.35m. The next lunar month commenced at 06h.54m. on 16th July. The Soura or solar month Mithuna or Gemini began with the ingress of the Sun into Gemini at 17h.l2m. on 15th June and ended at 04h.02m. on 16th July, when the Sun moved into Cancer. Therefore there were two New Moons during the solar month of Mithuna. There were two lunar months occurring in the Soura Mithuna month between 15th June and 16th July 2015. As both the months are Ashada the first one would go under the nomenclature of Adhika-Ashada and the second, as Nija-Aashada.
According Raman Ayanaamsa, the Soura Mithuna month would have begun on 14th June 2015 at 29h.48m. and ended at 29h.22m. on 15th July 2015 when the Soura month of Cancer commenced. The lunar month Ashada commenced only on 16th June at 19h.35m. This happened after the entry of the Sun into Mithuna. The next lunar month – Sravana – began on 16th July at 06h.54m. Before this happened Soura Cancer had already dawned on 15th July 2015. So, technically, according to Raman Ayanamsa there were two Amavasyas in the solar month of Mithuna. However, the Soura Kataka month from 15th July 2015 to 16th August 2015 would have them causing an Adhika Sravana.
In short, while there was Adhika Ashada lunar month during the year Manmatha according to Chaitra Paksha Ayanamsa, the Adhikamasa according to Raman Ayanamsa occurred only a month thereafter. Whichever school of Ayanamsa one may prefer to follow, the fact is that there was an Adhikamasa in the year Manmatha.
The differences in the Ayanamsa values followed by different schools can alter the timings of the solar ingresses and thereby, the reckoning of the solar months. It has to be noted that these differing values of Ayanamsa do not affect the Tithis and therefore, the lunar calendar. This is because the Tithi is only the gain factor of 12° of longitude of the Moon over that of the Sun. As both the longitudes of the Sun and the Moon will have only a common difference in tune with the Ayanamsa values, the Tithis and consequently, the timings of the Full or New Moons will not get affected.
The differences in the Ayanamsas bring only a shift in the exact timings of the solar ingresses into Rasis or signs. As the difference in computation is constant the occurrence of Adhikamasa, will be inevitable whatever the Ayanamsa value adopted. It can only shift its occurrence to a different point of time, in advance or subsequent to the reckoning according to a particular Ayanamsa. These dissimilarities are being pointed out only to highlight the perfect computational calendric principles underlying the Adhikamasa which every student of astrology should be aware of.
Generally, no religious festivals are observed in the Adhikamasa which is deemed to be Malamasa or polluted month.
Commencement of studies, Upanayana, entering a new house, signing of papers pertaining to the buying of a house, tonsure, marriage, commencement of construction, buying a car or signing any important papers and the like are not advised during Adhikamasa. However, there is no taboo for daily prayers, Japa, charity, reading scriptures, attending Satsangh and performing ceremonies relating to death and birth.
Kalavidhana gives an exception to this general rule. If any planet remains exalted during an Adhikamasa, the blemish for the month abates and all auspicious events can be performed. The last time an Adhikamasa took place in 2015, according to the Chaitra Paksha Ayanamsa, Jupiter was in Cancer till 14th July in exaltation. So the Adhika Ashada that prevailed from 16th June to 16th July 2015 got relieved of the sting,  at least for the period till 14th July. However, Adhika Sravana as per Raman Ayanamsa did not attract this exemption as no planet was exalted during that particular month.
The Adhikamasa in the Manmata year 2015-2016 took place in the month of Ashada Chaitra Paksha and during Sravana according to Raman Ayanamsa.
The Adhikamasas for some future years according to Chaitra Paksha Ayanamsa are as follows.


  • Vilambi Year in 2018-2019 during Jyeshta month.
  • Sharvari Year in 2020-2021 during Ashwija month
  • Shubhakritu Year in 2023-2024 during Sravana month.
  • Parabhava Year in 2026-2027 during Jyeshta month.


By referring to Raman Ephemeris for the particular year, one can easily find out whether the Adhikamasa occurs in that particular month or earlier or later. Whichever school of Ayanamsa one may prefer to follow, the fact is that the Adhikamasa can occur earlier or later than that reckoned as per Chaitra Paksha Ayanamsa.
Adhikamasa in Vilambi Year (2018-2019)
The next occurrence of an Adhikamasa will be in the year Vilambi and it will be an Adhika Jyeshta according to Chaitra Paksha Ayanamsa.

Jyeshta month begins with Sukla Pratipada on the 15th May 2018 at 17h.17m.26s..and ends on 14th June 2018 at 01h.12m.53s. The solar ingresses are on 15th May at 05h.02m. 55s. and on June 15th 2018 at 11h.36m.19s. according to Chaitra Paksha Ayanamsa. According to Raman Ayanamsa, they are on 13th May midnight and 13th June midnight. Therefore the Saura or solar month will not have two New Moons. However, this will happen in the next month between 13th June 2018 midnight and 15th July midnight. So the Adhikamasa according to Raman Ayanamsa will be Ashada.

Courtesy: Modern Astrology(V.S Kalyanaraman)