- For general context, see here.
History
- In Shaka 444 i.e. 522 CE, mean longitudes of the Old SS and Aryabhatiya etc. tallied almost exactly with the so called sayana i.e. tropical mean longitudes of planets as per modern astronomy.
“These are thus works like Grahalaghva and Makaranda, both of them having been based on the Surya Siddhanta formulae with some insignificant “beeja corrections”.”
“There are several Vakya panchangams in Tamil nadu, the famous being the Pampu (snake) panchangam, Thanigai Panchangam, Sri Rangam Panchangam, Garudan Panchangam, Arcot Sitarama Iyer panchangam and so on. There will invariably be a difference in timings between drik Ganitha and Vakya Panchangam. But they invariably take the Drik calculation to show correct timings of eclipses (so that they make believe their system is ancient and also accurate). Some of them, especially Arcot Sita Rama Iyer panchangam, make some predictions about weather and politics that have proved accurate. May be a case of making correct predictions from wrong data.”
“There is a textual record that till as late as 1996 the most reputed panchanga-maker of Kashmir [Vijayeshwar-Panchang] was giving the timings of tithi, nakshatra etc. as per “Khaṇḍa-khādyaka” a sixth century ‘‘handbook” of Brahmagupta, for the last about 100 years whereas he had switched over to “drik-ganita” for planetary positions very recently then!"
Errors
- Understanding precession in terms of trepidation (Details here.
- vAkya-panchAnga-s oft give erroneous results regarding graha-s
Yes, the vākya-s were written before H discovered evection & variation, but this would still bring the Moon within ~2-3 degrees.
the fact that the tables encoded by the candravākyas are out of date. The effort led by nityāgnihotrī śrīramaṇa śarmā aṇṇa aimed at doing pariśkāra of the vākyas (which are essentially shortcuts).
Location effects -
vAkya-s assume position to be astronomical lanka.
But, the position of the moon in the sky doesn’t depend much on whether you look up from “lanka” or shrIrangam. moon being 30 earth diameters away, location would make max diff of 1 / 30 radians = 1.91 deg only.
Conjunctions, eclipses
- This manifests in inability to precisely predicting eclipses.
- Sometimes saura-paxa-panchAnga-s are not even able to determine if an eclipse will “happen” or not.
- Some ritualists simply follow pop culture and used more accurate dRk-panchAnga-s for eclipse observances; while following vAkya-panchanga regarding parva-rituals! Such inconsistency!
- Around Jan 6, 2018 conjunction of Mars and Jupiter could be observed while they placed Mars still in 1st qtr about 1½° (three moon sizes) away.
- Apr 13, 2017: Vakya Panchanga said Budha supposedly in Ashvini 3rd qtr transited Surya in Bharani 4th qtr - but NASA showed Mercury passing Surya. TW
Wrong tithi boundaries.
Source of error - vAkya-panchAnga-s have obvious errors with regards to sun-moon conjunction (and consequently eclipse and end of amAvAsyA).
“The word “sankalpa” reminds me that we recite the daily “samkalpa” about Kalpa, Manvantara, Yuga, varsha etc. as per the Surya Siddhanta (instead of Aryabhatiya!!) but do not calculate even our horoscopes from the same work.”
2020 Solstice
June 21 2020 was a special day - it was the solstice day, there was an annular solar eclipse visible from India (with peak at 11:47:35 am IST), and it naturally was amAvAsyA until 11:47:35 am IST. vAkya-panchAnga-s had obvious errors with regards to sun-moon conjunction (and consequently eclipse and end of amAvAsyA) - so tithi junction was till 12:30 or so. Some ritualists simply followed pop culture and used more accurate dRk-panchAnga-s for eclipse observances; while following vAkya-panchanga regarding parva-rituals! Such inconsistency! So, they incorrectly conducted sthAlIpAka the following day. (Not to mention, they must have continued saying “uttarAyaNe” in their sankalpa-s as well.)
Correction
पुत्तिगे-पालिमारु-पेजावराडमारु-मठाः १९९९-तः दृक्-पञ्चाङ्गम् आश्रित्य साधारण-तिथि-निर्णयं कुर्वन्ति - “ग्रहण-क्षणं येन साधु गण्यते तद् ग्राह्यम्” इत्यर्थवतः कस्यचन वराह-पुराण-वाक्यस्य प्रेरणया।
नितराम् प्रशंसनीयम्।
ayana
- अयनचलनप्रतिक्रिया दृक्तुल्यताप्राधान्यम् च अन्यत्र + उक्तम्।