Mayapur or your location? Pre-1990 and post-1990 standards

One setting decides on which date you celebrate festivals and keep Ekādaśī. Please read this page once, and choose consciously.

Why it matters. The same festival or Ekādaśī can fall on different civil dates depending on this choice, and the Parana time (date, sunrise, Harivāsara) changes with it. The calendar supports both ISKCON standards, so the decision is yours — and your community’s.

The two standards

	Mayapur (pre-1990)	Current location (post-1990)
How the day is counted	The calendar of Śrī Māyāpur is followed in any time zone of the world, on the same calendar date as in Mayapur	Calculations are made on the local time of sunrise of the place where you are
ISKCON document	GBC resolution 53, 1988	GBC resolution 42, 1990
In ISKCON	Followed from the beginning until 1990	Proposed by the Calendar Research Committee and adopted in 1990
In the app	Option Use Shri Mayapur	Option Use ‘Current location’

What the documents say

Both resolutions are public. Here are the relevant paragraphs word for word.

GBC resolutions 1988, paragraph 53

That the GBC accepts the Yoga Pitha Gaudiya Panjika calendar as authoritative for ISKCON on the instructions of Srila Prabhupada. It is also Srila Prabhupada’s instructions that the Panjika be followed in any time zone of the world according to the same Calendar date as observed in Mayapur.

Sources: gbc.iskcon.org/1988 · prabhupadavision.com

GBC resolutions 1990, paragraph 42

That the report of the Calendar Research Committee is accepted in principle, with thanks. ISKCON temples throughout the world shall follow the official calendar calculated according to the conclusions of this report, which are:
a) That the calculations should be made based upon the local time of sunrise.
b) That a computerized method of calculations is acceptable.
c) That the length of a muhurta shall be calculated as a 15th part of the daytime and a 15th part of the nighttime.
d) That sunrise shall be defined as the time of calculated visibility of the upper limb of the sun at the horizon, and the time of sunset as the time of calculated disappearance of the upper limb of the sun at the horizon.
e) That the calculations shall be based upon the positions of the heavenly bodies as determined according to modern scientific astronomical observations.

Sources: gbc.iskcon.org/1990 · prabhupadavision.com

The difference in one line

1988: "… in any time zone of the world according to the same Calendar date as observed in Mayapur."
1990: "… based upon the local time of sunrise."

Point (d) of 1990 defines sunrise by the visibility of the upper limb of the sun, which corresponds to the Earth-sky horizon of the app; the Celestial horizon is a separate option — see Celestial and Earth-sky horizon.

If you want to know how it was in the early years, ask senior devotees of your community: ISKCON followed Mayapur timings until 1990.

Other calendars and this app

	GCAL	This app
Mayapur standard (pre-1990)	—	✔
Current location (post-1990)	✔	✔
Earth-sky horizon	✔	✔
Celestial horizon	—	✔

To reproduce the results of GCAL choose Current location and the Earth-sky horizon.

How to choose

Ask your Guru and your temple authorities which standard your community follows. If you are not sure, do not guess: wrong dates mean a missed fast or festival.
Set it in the app: Settings → Compatibility with GCal → Calculating the day when the event occurs — switch between Use Shri Mayapur and Use ‘Current location’. The app also asks about it during first-time setup.
Check the horizon option — Celestial or Earth-sky — because it shifts sunrise, and so the day.
After any change, the dates of events and Parana times are recalculated. Different approaches give different results — that is expected.

Will all dates differ between the two standards?

No. For most days the result is the same. The difference appears when a tithi begins or ends close to sunrise at your place compared with sunrise at Śrī Māyāpur.

Is one of them a bug?

No. They are two different rules for deciding the day, each with its own ISKCON document. The calendar simply lets you follow the one your community follows.