Panchang in Ipameri, Goiás, Brazil Mon 26 Dec 1921

Shiva’s Pradosh puja is done in pradosha, the 3 muhurtas after sunset. Trayodashi runs from 01:05 on Mon 26 Dec to 01:13 on Tue 27 Dec, so only Monday’s pradosha (18:49–20:58) 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: 324°–336° is the 28th, Krishna Trayodashi. A day takes the tithi in force at its sunrise, 05:37 here. Dwadashi ended at 01:05, before it. Trayodashi ends at 01:13 Tue, when the lead reaches 336°. The lead passed 180° at the full moon of 14 Dec, so the Moon is waning: Krishna paksha.

A day takes the tithi in force at its sunrise.

New Delhi · IST

Sunrise here, 07:11, came before Dwadashi ended at 09:35: this day reads Dwadashi.

Ipameri · UTC−3

Sunrise here, 05:37, came after Dwadashi ended at 01:05: this day reads Trayodashi.

The night of Sun 25 Dec ran from sunset 18:48 Sun to sunrise 05:37, 10 h 49 m. Cut into 15 muhurtas of 43 m, its 14th is Brahma Muhurta, the one before the last.

Daylight here, 05:37 to 18:49, splits into 8 choghadiyas of 1 h 39 m. Their names follow a fixed order that starts from the weekday, and each name is counted good, neutral or bad.

The night here, 18:49 to 05:38 Tue, splits into 8 choghadiyas of 1 h 21 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′. Anuradha spans 213°20′–226°40′; the Moon entered its pada 2 at 216°40′. It leaves at 22:31, for Jyeshtha.

Add the Sun's and the Moon's places among the stars: 251.3° + 217.6° = 468.9°, one full turn and 108.9°. Past the turn, cut into 27 parts of 13°20′, it gives the yoga: 106°40′–120°00′ is the 9th, Shula. It ends at 00:48 Tue, then Ganda.

A karana is half a tithi: 6° of the Moon's lead, so the first half of Trayodashi is Garaja and the second Vanija. Garaja runs until 13:06, when the lead reaches 330°; Vanija until 01:13 Tue.

A Hindu day runs from one sunrise to the next, not midnight to midnight. This one runs 05:37 to 05:38 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: Vrishchika gives Margashirsha. The Sun enters Dhanu on 15 Dec, inside the month. The next new moon, 29 Dec, finds it in Dhanu and begins Pausha.

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 29 Dec, with the Sun in Dhanu, begins Pausha. Until then this Krishna paksha reads Pausha here, and Margashirsha in the amanta count.

A samvat year begins with Chaitra, the month whose new moon finds the Sun in Meena: 8 Apr 1921, 06:04 Fri. Since then the Sun has moved 256.1° round the stars. Vikram Samvat numbers that year 1978; Shaka Samvat numbers it 1843.