Panchang in Ipameri, Goiás, Brazil Mon 4 Oct 2021

Shiva’s worship centres on nishitha, the midnight muhurta. Chaturdashi runs from 12:35 on Mon 4 Oct to 10:34 on Tue 5 Oct, so only Monday night’s nishitha (23:37–00:24 Tue) 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, 05:52 here. Dwadashi ended at 14:00 Sun, before it. Trayodashi ends at 12:35, when the lead reaches 336°. The lead passed 180° at the full moon of 20 Sep, so the Moon is waning: Krishna paksha.

The night of Sun 3 Oct ran from sunset 18:10 Sun to sunrise 05:52, 11 h 42 m. Cut into 15 muhurtas of 46 m, its 14th is Brahma Muhurta, the one before the last.

Daylight here, 05:52 to 18:10, splits into 8 choghadiyas of 1 h 32 m. Their names follow a fixed order that starts from the weekday, and each name is counted good, neutral or bad.

The night here, 18:10 to 05:51 Tue, splits into 8 choghadiyas of 1 h 27 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 Phalguni spans 133°20′–146°40′; the Moon entered its pada 2 at 136°40′. It leaves at 18:05, for Uttara Phalguni.

Add the Sun's and the Moon's places among the stars: 167.2° + 139.6° = 306.8°. The sum, cut into 27 parts of 13°20′, gives the yoga: 306°40′–320°00′ is the 24th, Shukla. It ends at 03:04 Tue, then Brahma.

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 01:23, when the lead reached 330°; Vanija runs until 12:35.

A Hindu day runs from one sunrise to the next, not midnight to midnight. This one runs 05:52 to 05:51 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 6 Oct, with the Sun in Kanya, begins Ashwina. Until then this Krishna paksha reads Ashwina here, and Bhadrapada in the amanta count.

A samvat year begins with Chaitra, the month whose new moon finds the Sun in Meena: 11 Apr 2021, 23:30 Sun. Since then the Sun has moved 168.9° round the stars. Vikram Samvat numbers that year 2078; Shaka Samvat numbers it 1943.