Panchang in Codcod, Western Visayas, Philippines Mon 18 Oct 2021

Shiva’s Pradosh puja is done in pradosha, the 3 muhurtas after sunset. Trayodashi runs from 20:09 on Sun 17 Oct to 20:37 on Mon 18 Oct, so only Monday’s pradosha (17:28–19:54) falls within it. No text giving Pradosh Vrat’s time was found; pradosha is Tithika’s convention.

Pradosh Vrat: every date in Codcod

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, 05:36 here. Dwadashi ended at 20:09 Sun, before it. Trayodashi ends at 20:37, when the lead reaches 156°. The lead passed 0° at the new moon of 6 Oct, so the Moon is waxing: Shukla paksha.

The night of Sun 17 Oct ran from sunset 17:28 Sun to sunrise 05:36, 12 h 8 m. Cut into 15 muhurtas of 48 m, its 14th is Brahma Muhurta, the one before the last.

Daylight here, 05:36 to 17:28, splits into 8 choghadiyas of 1 h 29 m. Their names follow a fixed order that starts from the weekday, and each name is counted good, neutral or bad.

The night here, 17:28 to 05:36 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′. Purva Bhadrapada spans 320°00′–333°20′; the Moon entered its pada 3 at 326°40′. It leaves at 13:19, for Uttara Bhadrapada.

Add the Sun's and the Moon's places among the stars: 180.6° + 329.2° = 509.8°, one full turn and 149.8°. Past the turn, cut into 27 parts of 13°20′, it gives the yoga: 146°40′–160°00′ is the 12th, Dhruva. It ends at 23:27, then Vyaghata.

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 08:20, when the lead reaches 150°; Taitila until 20:37.

A Hindu day runs from one sunrise to the next, not midnight to midnight. This one runs 05:36 to 05:36 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: Kanya gives Ashwina. The Sun enters Tula on 17 Oct, inside the month. The next new moon, 5 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 6 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: 12 Apr 2021, 10:30 Mon. Since then the Sun has moved 182.3° round the stars. Vikram Samvat numbers that year 2078; Shaka Samvat numbers it 1943.