Panchang in Sevan, Gegharkunik, Armenia Mon 20 Sep 2021

Purnima follows the tithi at sunrise. Purnima runs from 03:58 on Mon 20 Sep to 03:54 on Tue 21 Sep, so it holds sunrise only on Mon 20 Sep, at 06:45. No text giving Purnima’s time was found; sunrise is Tithika’s convention.

Purnima: every date in Sevan

The Moon gains on the Sun about 12° a day. Each 12° of lead is one tithi: 168°–180° is the 15th, Shukla Purnima. A day takes the tithi in force at its sunrise, 06:45 here. Chaturdashi ended at 03:58, before it. Purnima ends at 03:54 Tue, when the lead reaches 180°. The lead passed 0° at the new moon of 7 Sep, so the Moon is waxing: Shukla paksha.

The night of Sun 19 Sep ran from sunset 19:02 Sun to sunrise 06:45, 11 h 43 m. Cut into 15 muhurtas of 46 m, its 14th is Brahma Muhurta, the one before the last.

Daylight here, 06:45 to 19:00, splits into 8 choghadiyas of 1 h 31 m. Their names follow a fixed order that starts from the weekday, and each name is counted good, neutral or bad.

The night here, 19:00 to 06:46 Tue, splits into 8 choghadiyas of 1 h 28 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′. Purva Bhadrapada spans 320°00′–333°20′; the Moon entered its pada 1 at 320°. It leaves at 02:31 Tue, for Uttara Bhadrapada.

Add the Sun's and the Moon's places among the stars: 153.2° + 322.6° = 475.8°, one full turn and 115.8°. Past the turn, cut into 27 parts of 13°20′, it gives the yoga: 106°40′–120°00′ is the 9th, Shula. It ends at 13:52, then Ganda.

A karana is half a tithi: 6° of the Moon's lead, so the first half of Purnima is Vishti and the second Bava. Vishti runs until 15:52, when the lead reaches 174°; Bava until 03:54 Tue.

A Hindu day runs from one sunrise to the next, not midnight to midnight. This one runs 06:45 to 06:46 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: Simha gives Bhadrapada. The Sun enters Kanya on 16 Sep, inside the month. The next new moon, 6 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 7 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: 12 Apr 2021, 06:30 Mon. Since then the Sun has moved 154.9° round the stars. Vikram Samvat numbers that year 2078; Shaka Samvat numbers it 1943.