Panchang in Ipameri, Goiás, Brazil Tue 17 Oct 2017

Shiva’s worship centres on nishitha, the midnight muhurta. Chaturdashi runs from 16:38 on Tue 17 Oct to 16:43 on Wed 18 Oct, so only Tuesday night’s nishitha (00:34 Wed–01:20 Wed) 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, 06:42 here. Dwadashi ended at 16:56 Mon, before it. Trayodashi ends at 16:38, when the lead reaches 336°. The lead passed 180° at the full moon of 5 Oct, so the Moon is waning: Krishna paksha.

The night of Mon 16 Oct ran from sunset 19:13 Mon to sunrise 06:42, 11 h 29 m. Cut into 15 muhurtas of 45 m, its 14th is Brahma Muhurta, the one before the last.

Daylight here, 06:42 to 19:13, 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, 19:13 to 06:41 Wed, 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′. Uttara Phalguni spans 146°40′–160°00′; the Moon entered its pada 2 at 150°. It leaves at 23:08, for Hasta.

Add the Sun's and the Moon's places among the stars: 180.1° + 151.1° = 331.2°. The sum, cut into 27 parts of 13°20′, gives the yoga: 320°00′–333°20′ is the 25th, Brahma. It ends at 10:28, then Indra.

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 04:45, when the lead reached 330°; Vanija runs until 16:38.

A Hindu day runs from one sunrise to the next, not midnight to midnight. This one runs 06:42 to 06:41 Wed, so the hours after midnight still belong to Mangalawara.

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: Kanya gives Ashwina. The Sun enters Tula on 17 Oct, inside the month. The next new moon, 19 Oct, finds it in Tula and begins Kartika.

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 19 Oct, with the Sun in Tula, begins Kartika. Until then this Krishna paksha reads Kartika here, and Ashwina in the amanta count.

A samvat year begins with Chaitra, the month whose new moon finds the Sun in Meena: 27 Mar 2017, 23:57 Mon. Since then the Sun has moved 196.6° round the stars. Vikram Samvat numbers that year 2074; Shaka Samvat numbers it 1939.