Panchang in Diffa, Niger Sun 21 Oct 2018

Shiva’s Pradosh puja is done in pradosha, the 3 muhurtas after sunset. Trayodashi began at 17:01 on Sun 21 Oct, before that evening’s pradosha, and ended at 17:53 on Mon 22 Oct, partway into the next. The Nirnayasindhu takes the evening Trayodashi fills: Sun 21 Oct. No text giving Pradosh Vrat’s time was found; pradosha is Tithika’s convention.

Pradosh Vrat: every date in Diffa

The Moon gains on the Sun about 12° a day. Each 12° of lead is one tithi: 132°–144° is the 12th, Shukla Dwadashi. A day takes the tithi in force at its sunrise, 06:01 here. Ekadashi ended at 15:31 Sat, before it. Dwadashi ends at 17:01, when the lead reaches 144°. The lead passed 0° at the new moon of 9 Oct, so the Moon is waxing: Shukla paksha.

The night of Sat 20 Oct ran from sunset 17:47 Sat to sunrise 06:01, 12 h 14 m. Cut into 15 muhurtas of 48 m, its 14th is Brahma Muhurta, the one before the last.

Daylight here, 06:01 to 17:47, 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, 17:47 to 06:01 Mon, 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′. Purva Bhadrapada spans 320°00′–333°20′; the Moon entered its pada 1 at 320°. It leaves at 03:06 Mon, for Uttara Bhadrapada.

Add the Sun's and the Moon's places among the stars: 183.6° + 322.4° = 506°, one full turn and 146°. Past the turn, cut into 27 parts of 13°20′, it gives the yoga: 133°20′–146°40′ is the 11th, Vriddhi. It ends at 07:07, then Dhruva.

A karana is half a tithi: 6° of the Moon's lead, so the first half of Dwadashi is Bava and the second Balava. Bava ended at 04:20, when the lead reached 138°; Balava runs until 17:01.

A Hindu day runs from one sunrise to the next, not midnight to midnight. This one runs 06:01 to 06:01 Mon, so the hours after midnight still belong to Raviwara.

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: Kanya gives Ashwina. The Sun enters Tula on 17 Oct, inside the month. The next new moon, 7 Nov, finds it in Tula and begins Kartika.

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 9 Oct, with the Sun in Kanya, began Ashwina. This Shukla paksha reads Ashwina in both counts.

A samvat year begins with Chaitra, the month whose new moon finds the Sun in Meena: 17 Mar 2018, 14:11 Sat. Since then the Sun has moved 210.8° round the stars. Vikram Samvat numbers that year 2075; Shaka Samvat numbers it 1940.