Panchang in Sevan, Gegharkunik, Armenia Sun 20 Feb 1921

Shiva’s Pradosh puja is done in pradosha, the 3 muhurtas after sunset. Trayodashi runs from 22:59 on Sat 19 Feb to 19:30 on Sun 20 Feb, so it touches only Sunday’s pradosha (17:38–20:15). No text giving Pradosh Vrat’s time was found; pradosha is Tithika’s convention.

Pradosh Vrat: every date in Sevan

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, 06:48 here. Dwadashi ended at 23:01 Sat, before it. Trayodashi ends at 19:32, when the lead reaches 156°. The lead passed 0° at the new moon of 8 Feb, so the Moon is waxing: Shukla paksha.

The night of Sat 19 Feb ran from sunset 17:39 Sat to sunrise 06:48, 13 h 9 m. Cut into 15 muhurtas of 52 m, its 14th is Brahma Muhurta, the one before the last.

Daylight here, 06:48 to 17:40, splits into 8 choghadiyas of 1 h 21 m. Their names follow a fixed order that starts from the weekday, and each name is counted good, neutral or bad.

The night here, 17:40 to 06:46 Mon, splits into 8 choghadiyas of 1 h 38 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′. Pushya spans 93°20′–106°40′; the Moon entered its pada 2 at 96°40′. It leaves at 22:34, for Ashlesha.

Add the Sun's and the Moon's places among the stars: 308.2° + 96.8° = 405°, one full turn and 45°. Past the turn, cut into 27 parts of 13°20′, it gives the yoga: 40°00′–53°20′ is the 4th, Saubhagya. It ends at 19:15, then Shobhana.

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 09:18, when the lead reaches 150°; Taitila until 19:32.

A Hindu day runs from one sunrise to the next, not midnight to midnight. This one runs 06:48 to 06:46 Mon, so the hours after midnight still belong to Raviwara.

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: Makara gives Magha. The Sun enters Kumbha on 12 Feb, inside the month. The next new moon, 9 Mar, finds it in Kumbha and begins Phalguna.

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 8 Feb, with the Sun in Makara, began Magha. This Shukla paksha reads Magha in both counts.

A samvat year begins with Chaitra, the month whose new moon finds the Sun in Meena: 20 Mar 1920, 13:55 Sat. Since then the Sun has moved 331.4° round the stars. Vikram Samvat numbers that year 1977; Shaka Samvat numbers it 1842.