Panchang in Ipameri, Goiás, Brazil Sun 12 May 1991

Shiva’s worship centres on nishitha, the midnight muhurta. Chaturdashi runs from 07:27 on Sun 12 May to 04:43 on Mon 13 May, so only Sunday night’s nishitha (23:43–00:34 Mon) falls within it. No text giving Masik Shivratri’s time was found; nishitha is Tithika’s convention.

Masik Shivratri: every date in Ipameri

The Moon gains on the Sun about 12° a day. Each 12° of lead is one tithi: 324°–336° is the 28th, Krishna Trayodashi. A day takes the tithi in force at its sunrise, 06:29 here. Dwadashi ended at 09:38 Sat, before it. Trayodashi ends at 07:27, when the lead reaches 336°. The lead passed 180° at the full moon of 28 Apr, so the Moon is waning: Krishna paksha.

A day takes the tithi in force at its sunrise. Chaturdashi began at 07:27 and ended at 04:43 Mon, between the sunrises of 06:29 and 06:29 Mon. Sunday reads Trayodashi and Monday reads Amavasya: Chaturdashi is a kshaya tithi here.

The night of Sat 11 May ran from sunset 17:49 Sat to sunrise 06:29, 12 h 40 m. Cut into 15 muhurtas of 50 m, its 14th is Brahma Muhurta, the one before the last.

Daylight here, 06:29 to 17:48, splits into 8 choghadiyas of 1 h 24 m. Their names follow a fixed order that starts from the weekday, and each name is counted good, neutral or bad.

The night here, 17:48 to 06:29 Mon, splits into 8 choghadiyas of 1 h 35 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′. Ashwini spans 0°00′–13°20′; the Moon entered its pada 1 at 0°. It leaves at 23:49, for Bharani.

Add the Sun's and the Moon's places among the stars: 27.4° + 2.9° = 30.3°. The sum, cut into 27 parts of 13°20′, gives the yoga: 26°40′–40°00′ is the 3rd, Ayushmana. It ends at 21:34, then Saubhagya.

A karana is half a tithi: 6° of the Moon's lead, so the first half of Trayodashi is Garaja and the second Vanija. Garaja ended at 20:37 Sat, when the lead reached 330°; Vanija runs until 07:27.

A Hindu day runs from one sunrise to the next, not midnight to midnight. This one runs 06:29 to 06:29 Mon, so the hours after midnight still belong to Raviwara.

A month normally holds one sankranti, the Sun's entry into a new rashi. From 14 Apr 16:37 Sun to 14 May 01:35 Tue the Sun stayed in Mesha, entering Vrishabha at 14 May 22:25 Tue, after the new moon. A month with no sankranti is Adhika Vaishakha, before Vaishakha itself.

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 14 May, with the Sun in Mesha, begins Vaishakha (Adhik). Until then this Krishna paksha reads Vaishakha (Adhik) here, and Vaishakha (Adhik) in the amanta count.

A samvat year begins with Chaitra, the month whose new moon finds the Sun in Meena: 16 Mar 1991, 05:10 Sat. Since then the Sun has moved 55.9° round the stars. Vikram Samvat numbers that year 2048; Shaka Samvat numbers it 1913.