Panchang in Sevan, Gegharkunik, Armenia Fri 17 Apr 1981

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, 07:19 here. Dwadashi ended at 06:51 Thu, before it. Trayodashi ends at 08:40, when the lead reaches 156°. The lead passed 0° at the new moon of 5 Apr, so the Moon is waxing: Shukla paksha.

A day takes the tithi in force at its sunrise. Trayodashi began at 06:51 Thu, before sunrise at 07:20 Thu, and ends at 08:40, after the next sunrise at 07:19. Both days read Trayodashi: it is a vriddhi tithi here.

The night of Thu 16 Apr ran from sunset 20:39 Thu to sunrise 07:19, 10 h 40 m. Cut into 15 muhurtas of 42 m, its 14th is Brahma Muhurta, the one before the last.

Daylight here, 07:19 to 20:40, 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, 20:40 to 07:17 Sat, 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′. Uttara Phalguni spans 146°40′–160°00′; the Moon entered its pada 4 at 156°40′. It leaves at 09:45, for Hasta.

Add the Sun's and the Moon's places among the stars: 3.4° + 158.8° = 162.2°. The sum, cut into 27 parts of 13°20′, gives the yoga: 160°00′–173°20′ is the 13th, Vyaghata. It ends at 03:54 Sat, then Harshana.

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 ended at 19:43 Thu, when the lead reached 150°; Taitila runs until 08:40.

A Hindu day runs from one sunrise to the next, not midnight to midnight. This one runs 07:19 to 07:17 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: Meena gives Chaitra. The Sun enters Mesha on 13 Apr, inside the month. The next new moon, 4 May, finds it in Mesha and begins Vaishakha.

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 5 Apr, with the Sun in Meena, began Chaitra. This Shukla paksha reads Chaitra in both counts.

A samvat year begins with Chaitra, the month whose new moon finds the Sun in Meena: 5 Apr 1981, 01:19 Sun. Since then the Sun has moved 12° round the stars. Vikram Samvat numbers that year 2038; Shaka Samvat numbers it 1903.