Pradosham is the evening of Trayodashi. Ahnika Grantham decides the Maha Pradosham day in five ordered steps. Trayodashi at sunset gives the day. At sunset on two days, the second, if its evening lasts half a nazhigai. At sunset on neither, the day it arrives within 6 nazhigai after sunset. For the date itself, the printed almanac of your tradition decides. A book's rule explains a date; it does not overrule the almanac.
☕ The five steps, in order
Ahnika Grantham gives these steps where it speaks of the evening as a time when Vedic study pauses (Ahnika Grantham, Vol. 1 (Sri Ahobila Mutt), p. 318). A step is reached only when the one before it fails, so the order is part of the rule.
Step 1. If Trayodashi stands at sunset, that evening is the Maha Pradosham.
Step 2. If Trayodashi stands at sunset on two evenings in a row, take the second.
Step 3. But the second evening's pradosham must last at least half a nazhigai (12 minutes). If it is shorter, go back to the first evening.
Step 4. If Trayodashi stands at sunset on neither evening, take the evening it arrives within 6 nazhigai (2 hours 24 minutes) after sunset.
Step 5. If it arrives later than 6 nazhigai after sunset, take the second evening.
At a glance
- Chaturthi pradosham: Chaturthi arrives 9 nazhigai after sunset, or Chaturthi is present for 2 nazhigai after sunset.
- Saptami pradosham: Saptami is present 15 nazhigai after sunset, or Saptami lasts 1 nazhigai after sunset.
- What Nava does: Nava's calendar gives Pradosham on the last day Trayodashi is present during the pradosha kala, the 90 minutes after sunset. It does not run these five steps, and it names no Maha Pradosham, Chaturthi pradosham or Saptami pradosham.
- Nava does not compute this rule. This page explains it as the books give it.
Frequently asked questions
Is Maha Pradosham the same as the Pradosham in my calendar?
Not always. Most calendars give a Pradosham on each Trayodashi evening. This page is about one book’s ordered rule for the Maha Pradosham day, which can pick a different evening when Trayodashi spans two.
What is half a nazhigai?
12 minutes. One nazhigai is 24 minutes, and sixty make a day.
Does Nava show the Maha Pradosham?
No. Nava gives the Pradosham day only. For a Maha Pradosham, follow your almanac.
Deep dive: two evenings, worked through
Sunset 18:00 on both days.
🌇 Steps 2 and 3
Trayodashi begins Monday 17:00 and ends Tuesday 18:05.
- It stands at sunset on both evenings, so step 2 points to Tuesday.
- On Tuesday it lasts only 5 minutes past sunset, under half a nazhigai (12 minutes). Step 3 sends the day back to Monday.
🌙 Steps 4 and 5
Trayodashi begins Monday 19:30 and ends Tuesday 17:00, so it stands at neither sunset.
- It arrives 1 hour 30 minutes after Monday's sunset, within 6 nazhigai: step 4 takes Monday.
- Had it arrived at 21:00, 3 hours after sunset and past 6 nazhigai, step 5 would take Tuesday.
🔗 Read first
This page builds on Pradosham, the sunset twilight window, which explains the evening window itself.