Panchang in Davinópolis, Maranhão, Brazil Mon 13 Jun 2011

Shiva’s Pradosh puja is done in pradosha, the 3 muhurtas after sunset. Trayodashi runs from 23:50 on Sun 12 Jun to 21:21 on Mon 13 Jun, so only Monday’s pradosha (18:03–20:30) falls within it. No text giving Pradosh Vrat’s time was found; pradosha is Tithika’s convention.

Pradosh Vrat: every date in Davinópolis

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, 06:15 here. Dwadashi ended at 23:50 Sun, before it. Trayodashi ends at 21:21, when the lead reaches 156°. The lead passed 0° at the new moon of 1 Jun, so the Moon is waxing: Shukla paksha.

A day takes the tithi in force at its sunrise.

New Delhi · IST

Sunrise here, 05:22, came before Dwadashi ended at 08:20: this day reads Dwadashi.

Davinópolis · UTC−3

Sunrise here, 06:15, came after Dwadashi ended at 23:50 Sun: this day reads Trayodashi.

The night of Sun 12 Jun ran from sunset 18:03 Sun to sunrise 06:15, 12 h 12 m. Cut into 15 muhurtas of 48 m, its 14th is Brahma Muhurta, the one before the last.

Daylight here, 06:15 to 18:03, splits into 8 choghadiyas of 1 h 28 m. Their names follow a fixed order that starts from the weekday, and each name is counted good, neutral or bad.

The night here, 18:03 to 06:15 Tue, splits into 8 choghadiyas of 1 h 31 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′. Vishakha spans 200°00′–213°20′; the Moon entered its pada 2 at 203°20′. It leaves at 19:11, for Anuradha.

Add the Sun's and the Moon's places among the stars: 58° + 205.6° = 263.6°. The sum, cut into 27 parts of 13°20′, gives the yoga: 253°20′–266°40′ is the 20th, Shiva. It ends at 11:00, then Siddha.

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 10:34, when the lead reaches 150°; Taitila until 21:21.

A Hindu day runs from one sunrise to the next, not midnight to midnight. This one runs 06:15 to 06:15 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: Vrishabha gives Jyeshtha. The Sun enters Mithuna on 15 Jun, inside the month. The next new moon, 1 Jul, finds it in Mithuna and begins Ashadha.

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 1 Jun, with the Sun in Vrishabha, began Jyeshtha. This Shukla paksha reads Jyeshtha in both counts.

A samvat year begins with Chaitra, the month whose new moon finds the Sun in Meena: 3 Apr 2011, 11:32 Sun. Since then the Sun has moved 68.5° round the stars. Vikram Samvat numbers that year 2068; Shaka Samvat numbers it 1933.