Panchang in Codcod, Western Visayas, Philippines Sat 6 Jul 2013

Shiva’s worship centres on nishitha, the midnight muhurta. Chaturdashi runs from 10:18 on Sat 6 Jul to 12:49 on Sun 7 Jul, so only Saturday night’s nishitha (23:29–00:14 Sun) falls within it. No text giving Masik Shivratri’s time was found; nishitha is Tithika’s convention.

Masik Shivratri: every date in Codcod

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, 05:30 here. Dwadashi ended at 07:48 Fri, before it. Trayodashi ends at 10:18, when the lead reaches 336°. The lead passed 180° at the full moon of 23 Jun, so the Moon is waning: Krishna paksha.

The night of Fri 5 Jul ran from sunset 18:13 Fri to sunrise 05:30, 11 h 17 m. Cut into 15 muhurtas of 45 m, its 14th is Brahma Muhurta, the one before the last.

Daylight here, 05:30 to 18:13, 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 night here, 18:13 to 05:30 Sun, 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 fixed stars divide the Moon's path into 27 nakshatras of 13°20′, each in 4 padas of 3°20′. Mrigashira spans 53°20′–66°40′; the Moon entered its pada 1 at 53°20′. It leaves at 07:40 Sun, for Ardra.

Add the Sun's and the Moon's places among the stars: 80° + 53.8° = 133.8°. The sum, cut into 27 parts of 13°20′, gives the yoga: 133°20′–146°40′ is the 11th, Vriddhi. It ends at 05:48 Sun, then Dhruva.

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 21:02 Fri, when the lead reached 330°; Vanija runs until 10:18.

A Hindu day runs from one sunrise to the next, not midnight to midnight. This one runs 05:30 to 05:30 Sun, so the hours after midnight still belong to Shaniwara.

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: Vrishabha gives Jyeshtha. The Sun enters Mithuna on 15 Jun, inside the month. The next new moon, 8 Jul, finds it in Mithuna and begins Ashadha.

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 8 Jul, with the Sun in Mithuna, begins Ashadha. Until then this Krishna paksha reads Ashadha here, and Jyeshtha in the amanta count.

A samvat year begins with Chaitra, the month whose new moon finds the Sun in Meena: 10 Apr 2013, 17:35 Wed. Since then the Sun has moved 83.4° round the stars. Vikram Samvat numbers that year 2070; Shaka Samvat numbers it 1935.