Panchang in Codcod, Western Visayas, Philippines Mon 6 Oct 1980

Shiva’s Pradosh puja is done in pradosha, the 3 muhurtas after sunset. Trayodashi runs from 03:40 on Mon 6 Oct to 05:54 on Tue 7 Oct, so only Monday’s pradosha (17:34–19:58) 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: 324°–336° is the 28th, Krishna Trayodashi. A day takes the tithi in force at its sunrise, 05:35 here. Dwadashi ended at 03:40, before it. Trayodashi ends at 05:54 Tue, when the lead reaches 336°. The lead passed 180° at the full moon of 24 Sep, so the Moon is waning: Krishna paksha.

A day takes the tithi in force at its sunrise. Trayodashi began at 03:40, before sunrise at 05:35, and ends at 05:54 Tue, after the next sunrise at 05:35 Tue. Both days read Trayodashi: it is a vriddhi tithi here.

The night of Sun 5 Oct ran from sunset 17:35 Sun to sunrise 05:35, 12 h 0 m. Cut into 15 muhurtas of 48 m, its 14th is Brahma Muhurta, the one before the last.

Daylight here, 05:35 to 17:34, 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, 17:34 to 05:35 Tue, splits into 8 choghadiyas of 1 h 30 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 Phalguni spans 133°20′–146°40′; the Moon entered its pada 1 at 133°20′. It leaves at 06:49 Tue, for Uttara Phalguni.

Add the Sun's and the Moon's places among the stars: 169.2° + 134.1° = 303.3°. The sum, cut into 27 parts of 13°20′, gives the yoga: 293°20′–306°40′ is the 23rd, Shubha. It ends at 11:49, then Shukla.

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 16:45, when the lead reaches 330°; Vanija until 05:54 Tue.

A Hindu day runs from one sunrise to the next, not midnight to midnight. This one runs 05:35 to 05:35 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: Simha gives Bhadrapada. The Sun enters Kanya on 16 Sep, inside the month. The next new moon, 9 Oct, finds it in Kanya and begins Ashwina.

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, begins Ashwina. Until then this Krishna paksha reads Ashwina here, and Bhadrapada in the amanta count.

A samvat year begins with Chaitra, the month whose new moon finds the Sun in Meena: 17 Mar 1980, 02:55 Mon. Since then the Sun has moved 196.4° round the stars. Vikram Samvat numbers that year 2037; Shaka Samvat numbers it 1902.