On "Planetary Period Calculations"

By Syamasundar das, 12.5 2015

This is in response to "Planetary Period Calculations: 360 Day Years, or 365? - Part Two" by Dharmapad das.

I recently came across this statement from Bhaskaracarya's Siddhanta-siromani, and his ownVasana commentary on the text. (From Bhaktisiddhanta's Bengali translation.) In it he clearly explains what the different standards, sauramana (solar), chandramana (lunar), savana(civil), nakshatramana (sidereal) are used for. [I have edited it slightly for consistency.]

"The authors of the Samhitas tell us that the year of the Jupiter (Barhaspatya Samvatsara) is measured using the mean sidereal revolution of Jupiter. The humans however use a mixture of four standards to measure time.

"The humans use solar standard to determine year, northern or southern path of a planet (ayana ), seasons and yugas. They use lunar standard for the determination of months and lunar days (tithi). The civil standard (savana) is used for the determination of special prayers (vrata), fasting (upavasa) and treatment of disease. The sidereal standard is used for the determination of ghatikas."

Siddhanta Siromani 1.30-31

"Now the Jupiter reckoning and human reckoning is stated. The first half is simple and clear."

"The human reckoning is a mixed one: year, ayana, rtu and yuga are calculated by Vsolar. The months and tithis are calculated by lunar. Penances, fasting etc. are calculated on the basis of civil. Ghatika and so on are calculated on the basis of nakshatramana."

Vasana Commentary 1. 30-31

So from this it becomes very clear that we should use the solar year of 365.25 days fordetermining the length of a year and not the savana year of 360 days. This is exactly the same as what Mantresvara is advocating in his Phala Dipika.

To see the original text in context go here.

Regarding the status of Siddhanta-siromani

In Bhaktisiddhanta's introduction to Siddhanta Siromani he tells us:

"that in mathematical astronomy there are four sub-branches: siddhanta, tantra, karana and sarini. The branch of mathematical astronomy based on observation of planets and stars and their mathematical aspects is called siddhanta. The branch of mathematical astronomy dealing with the hypotheses on siddhanta and its elaborate explanation is called tantra. The branch based on useable mathematics to determine the results of siddhanta is called karana. The tables of calculations (ephemerides) made using the karana texts for calendars, horoscopes etc., are called sarini. An example of a siddhanta text is Surya Siddhanta. An example of a tantra text isSiddhanta Siromani, which is an elaborate and superexcellent commentary by Bhaskaracarya on the Surya Siddhanta. Examples of karana texts areGrahalaghava, and Karana Kutuhala. Examples of sarini are Makaranda andDinakaumadi etc."

There will always be someone with a different opinion but if I have to choose between the opinion of Bhaktisiddhanta Sarasvati Thakura, a greatly learned scholar in the subject, and Dharmapada Prabhu, then with confidence we shall cleave to the opinion of our acarya Bhaktisiddhanta regarding Siddhanta-siromani. Thus it is authoritatively and conclusively shown that for the purposes of calculating a year in Vimshottari Mahadasha we use the motion of the Sun, which is equivalent to approximately 365.25 days/year.

Reference:

Goswami, Danavir, 2007, compiler and editor of English translation of Bhaskaracarya's,Siddhanta-siromani with his own Vasana commentary, originally edited by Sri Bimala Prasada Siddhanta Saraswati along with his Bengali translation, Rupanuga Vedic College, Kansas City, MO.

dasa dasa anu dasa
Shyamasundara Dasa
krsne matirastu
www.ShyamasundaraDasa.com

The quality of mercy is not strain'd, 
It droppeth as the gentle rain from heaven.