Panchang in Devarshola, Tamil Nadu Thu 18 Aug 2016

The rakhi is tied in aparahna, the fourth fifth of the day, outside bhadra. Purnima runs from 16:27 on Wed 17 Aug to 14:56 on Thu 18 Aug, so it touches only Thursday’s aparahna (13:42–16:12). Every reading takes that day.

Raksha Bandhan: every date in Devarshola

Purnima follows the tithi at sunrise. Purnima runs from 16:27 on Wed 17 Aug to 14:56 on Thu 18 Aug, so it holds sunrise only on Thu 18 Aug, at 06:13. No text giving Purnima’s time was found; sunrise is Tithika’s convention.

Purnima: every date in Devarshola

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, 06:13 here. Chaturdashi ended at 16:27 Wed, before it. Purnima ends at 14:56, when the lead reaches 180°. The lead passed 0° at the new moon of 3 Aug, so the Moon is waxing: Shukla paksha.

The night of Wed 17 Aug ran from sunset 18:42 Wed to sunrise 06:13, 11 h 31 m. Cut into 15 muhurtas of 46 m, its 14th is Brahma Muhurta, the one before the last.

Daylight here, 06:13 to 18:42, splits into 8 choghadiyas of 1 h 33 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 06:14 Fri, 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 fixed stars divide the Moon's path into 27 nakshatras of 13°20′, each in 4 padas of 3°20′. Dhanishtha spans 293°20′–306°40′; the Moon entered its pada 2 at 296°40′. It leaves at 23:21, for Shatabhisha.

Add the Sun's and the Moon's places among the stars: 121.4° + 296.7° = 418.1°, one full turn and 58.1°. Past the turn, cut into 27 parts of 13°20′, it gives the yoga: 53°20′–66°40′ is the 5th, Shobhana. It ends at 19:58, then Atiganda.

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 ended at 03:45, when the lead reached 174°; Bava runs until 14:56.

A Hindu day runs from one sunrise to the next, not midnight to midnight. This one runs 06:13 to 06:14 Fri, so the hours after midnight still belong to Guruwara.

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: Karka gives Shravana. The Sun enters Simha on 16 Aug, inside the month. The next new moon, 1 Sep, finds it in Simha and begins Bhadrapada.

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 3 Aug, with the Sun in Karka, began Shravana. This Shukla paksha reads Shravana in both counts.

A samvat year begins with Chaitra, the month whose new moon finds the Sun in Meena: 7 Apr 2016, 16:53 Thu. Since then the Sun has moved 127.4° round the stars. Vikram Samvat numbers that year 2073; Shaka Samvat numbers it 1938.