Panchang in Hetauda, Bagmati Province, Nepal Mon 8 May 2017

Shiva’s Pradosh puja is done in pradosha, the 3 muhurtas after sunset. Trayodashi runs from 21:57 on Sun 7 May to 23:31 on Mon 8 May, so only Monday’s pradosha (18:42–20:50) falls within it. No text giving Pradosh Vrat’s time was found; pradosha is Tithika’s convention.

Pradosh Vrat: every date in Hetauda

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, 05:20 here. Dwadashi ended at 21:57 Sun, before it. Trayodashi ends at 23:31, when the lead reaches 156°. The lead passed 0° at the new moon of 26 Apr, so the Moon is waxing: Shukla paksha.

The night of Sun 7 May ran from sunset 18:41 Sun to sunrise 05:20, 10 h 39 m. Cut into 15 muhurtas of 42 m, its 14th is Brahma Muhurta, the one before the last.

Daylight here, 05:20 to 18:42, splits into 8 choghadiyas of 1 h 40 m. Their names follow a fixed order that starts from the weekday, and each name is counted good, neutral or bad.

The night here, 18:42 to 05:20 Tue, splits into 8 choghadiyas of 1 h 19 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′. Hasta spans 160°00′–173°20′; the Moon entered its pada 4 at 170°. It leaves at 09:58, for Chitra.

Add the Sun's and the Moon's places among the stars: 23.5° + 171° = 194.5°. The sum, cut into 27 parts of 13°20′, gives the yoga: 186°40′–200°00′ is the 15th, Vajra. It ends at 15:25, then Siddhi.

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 10:42, when the lead reaches 150°; Taitila until 23:31.

A Hindu day runs from one sunrise to the next, not midnight to midnight. This one runs 05:20 to 05:20 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: Mesha gives Vaishakha. The Sun enters Vrishabha on 14 May, inside the month. The next new moon, 26 May, finds it in Vrishabha and begins Jyeshtha.

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 26 Apr, with the Sun in Mesha, began Vaishakha. This Shukla paksha reads Vaishakha in both counts.

A samvat year begins with Chaitra, the month whose new moon finds the Sun in Meena: 28 Mar 2017, 08:42 Tue. Since then the Sun has moved 40° round the stars. Vikram Samvat numbers that year 2074; Shaka Samvat numbers it 1939.