Panchang in Ipameri, Goiás, Brazil Mon 23 Nov 2015

Shiva’s Pradosh puja is done in pradosha, the 3 muhurtas after sunset. Trayodashi runs from 05:47 on Mon 23 Nov to 02:43 on Tue 24 Nov, so only Monday’s pradosha (19:30–21:41) falls within it. No text giving Pradosh Vrat’s time was found; pradosha is Tithika’s convention.

Pradosh Vrat: every date in Ipameri

The Moon gains on the Sun about 12° a day. Each 12° of lead is one tithi: 144°–156° is the 13th, Shukla Trayodashi. A day takes the tithi in force at its sunrise, 06:28 here. Dwadashi ended at 05:47, before it. Trayodashi ends at 02:43 Tue, when the lead reaches 156°. The lead passed 0° at the new moon of 11 Nov, so the Moon is waxing: Shukla paksha.

A day takes the tithi in force at its sunrise.

New Delhi · IST

Sunrise here, 06:49, came before Dwadashi ended at 13:17: this day reads Dwadashi.

Ipameri · UTC−2

Sunrise here, 06:28, came after Dwadashi ended at 05:47: this day reads Trayodashi.

The night of Sun 22 Nov ran from sunset 19:29 Sun to sunrise 06:28, 10 h 59 m. Cut into 15 muhurtas of 43 m, its 14th is Brahma Muhurta, the one before the last.

Daylight here, 06:28 to 19:30, splits into 8 choghadiyas of 1 h 37 m. Their names follow a fixed order that starts from the weekday, and each name is counted good, neutral or bad.

The night here, 19:30 to 06:28 Tue, splits into 8 choghadiyas of 1 h 22 m. Their names follow a fixed order that starts from the weekday, and each name is counted good, neutral or bad.

The fixed stars divide the Moon's path into 27 nakshatras of 13°20′, each in 4 padas of 3°20′. Ashwini spans 0°00′–13°20′; the Moon entered its pada 1 at 0°. It leaves at 02:28 Tue, for Bharani.

Add the Sun's and the Moon's places among the stars: 216.6° + 1° = 217.6°. The sum, cut into 27 parts of 13°20′, gives the yoga: 213°20′–226°40′ is the 17th, Vyatipata. It ends at 20:09, then Variyana.

A karana is half a tithi: 6° of the Moon's lead, so the first half of Trayodashi is Kaulava and the second Taitila. Kaulava runs until 16:16, when the lead reaches 150°; Taitila until 02:43 Tue.

A Hindu day runs from one sunrise to the next, not midnight to midnight. This one runs 06:28 to 06:28 Tue, so the hours after midnight still belong to Somawara.

An amanta month runs from new moon to new moon and takes its name from the rashi the Sun is in at the new moon that begins it: Tula gives Kartika. The Sun enters Vrishchika on 16 Nov, inside the month. The next new moon, 11 Dec, finds it in Vrishchika and begins Margashirsha.

A purnimanta month runs from full moon to full moon, so its waning half comes first. It shares its name with the amanta month that its second half falls in: the new moon of 11 Nov, with the Sun in Tula, began Kartika. This Shukla paksha reads Kartika in both counts.

A samvat year begins with Chaitra, the month whose new moon finds the Sun in Meena: 20 Mar 2015, 06:36 Fri. Since then the Sun has moved 241.2° round the stars. Vikram Samvat numbers that year 2072; Shaka Samvat numbers it 1937.