Panchang in Codcod, Western Visayas, Philippines Sat 26 Sep 2015

Shiva’s Pradosh puja is done in pradosha, the 3 muhurtas after sunset. Trayodashi runs from 21:30 on Fri 25 Sep to 18:13 on Sat 26 Sep, so it touches only Saturday’s pradosha (17:41–20:04). 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 21:30 Fri, before it. Trayodashi ends at 18:13, when the lead reaches 156°. The lead passed 0° at the new moon of 13 Sep, so the Moon is waxing: Shukla paksha.

The night of Fri 25 Sep ran from sunset 17:41 Fri to sunrise 05:36, 11 h 55 m. Cut into 15 muhurtas of 47 m, its 14th is Brahma Muhurta, the one before the last.

Daylight here, 05:36 to 17:41, 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 night here, 17:41 to 05:36 Sun, 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 fixed stars divide the Moon's path into 27 nakshatras of 13°20′, each in 4 padas of 3°20′. Shatabhisha spans 306°40′–320°00′; the Moon entered its pada 1 at 306°40′. It leaves at 02:17 Sun, for Purva Bhadrapada.

Add the Sun's and the Moon's places among the stars: 158.4° + 307.1° = 465.5°, one full turn and 105.5°. Past the turn, cut into 27 parts of 13°20′, it gives the yoga: 93°20′–106°40′ is the 8th, Dhriti. It ends at 07:21, then Shula.

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 07:54, when the lead reaches 150°; Taitila until 18:13.

A Hindu day runs from one sunrise to the next, not midnight to midnight. This one runs 05:36 to 05:36 Sun, so the hours after midnight still belong to Shaniwara.

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 17 Sep, inside the month. The next new moon, 13 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 13 Sep, with the Sun in Simha, began Bhadrapada. This Shukla paksha reads Bhadrapada in both counts.

A samvat year begins with Chaitra, the month whose new moon finds the Sun in Meena: 20 Mar 2015, 17:36 Fri. Since then the Sun has moved 183° round the stars. Vikram Samvat numbers that year 2072; Shaka Samvat numbers it 1937.