Positional Astronomy Centre Panchang
The Positional Astronomy Centre (PAC) of the India Meteorological Department, Kolkata, is the Government of India's official publishing unit for the Rashtriya Panchang, Indian Astronomical Ephemeris, and the Saka calendar. PAC took over from the Calendar Reform Committee in 1955.
Key Facts
| Region | India (PAC, Kolkata) |
| Language | Multi-lingual (14 Indian languages) |
| Publisher | Positional Astronomy Centre (PAC), India Meteorological Department, Kolkata |
| Founder | PAC established 1 December 1955 |
| Founded | 1955 (PAC); first Rashtriya Panchang 1957 |
| Calculation | Drik Ganita with Lahiri Ayanamsa |
| Website | packolkata.imd.gov.in |
| Where to Get | PAC office Kolkata, Controller of Publications Delhi, IMD website |
PAC's Role
The Positional Astronomy Centre (PAC) is the unit within IMD Kolkata that prepares all official Government of India astronomical and panchang publications — the Rashtriya Panchang, the Indian Astronomical Ephemeris, planetary positions tables, and eclipse predictions. PAC publications are the reference for the Gazette of India, All India Radio, Doordarshan, and government calendar dates.
How Positional Astronomy Centre Panchang arrives at a date
Positional Astronomy Centre Panchang is calculated using Drik Ganita with Lahiri Ayanamsa. Drik Ganita means the positions of the sun and moon are computed for the moment being asked about, rather than read from the pre-computed mean-motion tables of the older Vakya method, and the Lahiri ayanamsa is the offset between the tropical and sidereal zodiacs that India adopted as its national standard.
That is the same basis the panchangam on this site is computed on, so the tithi, nakshatra, yoga and karana published here are arrived at the same way. What this site does not do is reproduce Positional Astronomy Centre Panchang: the figures here are computed for the date and place asked for, and no attempt is made to reconcile them with a printed edition.
Questions about Positional Astronomy Centre Panchang
Can a festival fall on a different day in Positional Astronomy Centre Panchang than on this site?
It can. The observance day is set by the tithi running at sunrise, and sunrise moves with longitude, so a tithi that begins in the hours either side of dawn can start before sunrise in India and after sunrise somewhere else. An edition prepared for one region and a calculation made for another city then differ by a day on that observance while agreeing on everything around it.
Where can readers get Positional Astronomy Centre Panchang?
Through PAC office Kolkata, Controller of Publications Delhi, IMD website. The publisher is online at packolkata.imd.gov.in. A panchangam is an annual publication: a copy covers one samvatsara and is replaced each year rather than kept as a standing reference.
Does this site publish the dates printed in Positional Astronomy Centre Panchang?
No. This page is a directory entry for a printed publication. Positional Astronomy Centre Panchang is published by Positional Astronomy Centre (PAC), India Meteorological Department, Kolkata, prepared in 14 Indian languages for readers in India. The daily panchangam on this site is computed independently and is not a reproduction of Positional Astronomy Centre Panchang or of any other printed edition.