Panchang in Thazhecode, Kerala Fri 15 Dec 2017

Shiva’s Pradosh puja is done in pradosha, the 3 muhurtas after sunset. Trayodashi runs from 05:08 on Fri 15 Dec to 07:10 on Sat 16 Dec, so only Friday’s pradosha (18:05–20:35) falls within it. No text giving Pradosh Vrat’s time was found; pradosha is Tithika’s convention.

Pradosh Vrat: every date in Thazhecode

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, 06:37 here. Dwadashi ended at 05:08, before it. Trayodashi ends at 07:10 Sat, when the lead reaches 336°. The lead passed 180° at the full moon of 3 Dec, so the Moon is waning: Krishna paksha.

A day takes the tithi in force at its sunrise. Trayodashi began at 05:08, before sunrise at 06:37, and ends at 07:10 Sat, after the next sunrise at 06:37 Sat. Both days read Trayodashi: it is a vriddhi tithi here.

The night of Thu 14 Dec ran from sunset 18:04 Thu to sunrise 06:37, 12 h 33 m. Cut into 15 muhurtas of 50 m, its 14th is Brahma Muhurta, the one before the last.

Daylight here, 06:37 to 18:05, splits into 8 choghadiyas of 1 h 26 m. Their names follow a fixed order that starts from the weekday, and each name is counted good, neutral or bad.

The night here, 18:05 to 06:37 Sat, splits into 8 choghadiyas of 1 h 34 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 01:30 Sat, for Anuradha.

Add the Sun's and the Moon's places among the stars: 239.1° + 203.8° = 442.9°, one full turn and 82.9°. Past the turn, cut into 27 parts of 13°20′, it gives the yoga: 80°00′–93°20′ is the 7th, Sukarma. It ends at 01:37 Sat, then Dhriti.

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 18:07, when the lead reaches 330°; Vanija until 07:10 Sat.

A Hindu day runs from one sunrise to the next, not midnight to midnight. This one runs 06:37 to 06:37 Sat, so the hours after midnight still belong to Shukrawara.

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: Vrishchika gives Margashirsha. The Sun enters Dhanu on 16 Dec, inside the month. The next new moon, 18 Dec, finds it in Dhanu and begins Pausha.

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 18 Dec, with the Sun in Dhanu, begins Pausha. Until then this Krishna paksha reads Pausha here, and Margashirsha in the amanta count.

A samvat year begins with Chaitra, the month whose new moon finds the Sun in Meena: 28 Mar 2017, 08:27 Tue. Since then the Sun has moved 255.6° round the stars. Vikram Samvat numbers that year 2074; Shaka Samvat numbers it 1939.