Panchang in Chahārbāgh, Alborz Province, Iran Fri 3 Apr 1981

Shiva’s worship centres on nishitha, the midnight muhurta. Chaturdashi runs from 06:28 on Fri 3 Apr to 03:20 on Sat 4 Apr, so only Friday night’s nishitha (23:47–00:32 Sat) falls within it. No text giving Masik Shivratri’s time was found; nishitha is Tithika’s convention.

Masik Shivratri: every date in Chahārbāgh

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, 05:50 here. Dwadashi ended at 09:02 Thu, before it. Trayodashi ends at 06:28, when the lead reaches 336°. The lead passed 180° at the full moon of 20 Mar, so the Moon is waning: Krishna paksha.

A day takes the tithi in force at its sunrise. Chaturdashi began at 06:28 and ended at 03:20 Sat, between the sunrises of 05:50 and 05:49 Sat. Friday reads Trayodashi and Saturday reads Amavasya: Chaturdashi is a kshaya tithi here.

The night of Thu 2 Apr ran from sunset 18:29 Thu to sunrise 05:50, 11 h 21 m. Cut into 15 muhurtas of 45 m, its 14th is Brahma Muhurta, the one before the last.

Daylight here, 05:50 to 18:29, splits into 8 choghadiyas of 1 h 34 m. Their names follow a fixed order that starts from the weekday, and each name is counted good, neutral or bad.

The night here, 18:29 to 05:49 Sat, splits into 8 choghadiyas of 1 h 25 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 Bhadrapada spans 320°00′–333°20′; the Moon entered its pada 2 at 323°20′. It leaves at 18:56, for Uttara Bhadrapada.

Add the Sun's and the Moon's places among the stars: 349.7° + 325.3° = 675°, one full turn and 315°. Past the turn, cut into 27 parts of 13°20′, it gives the yoga: 306°40′–320°00′ is the 24th, Shukla. It ends at 13:34, 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 19:50 Thu, when the lead reached 330°; Vanija runs until 06:28.

A Hindu day runs from one sunrise to the next, not midnight to midnight. This one runs 05:50 to 05:49 Sat, so the hours after midnight still belong to Shukrawara.

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: Kumbha gives Phalguna. The Sun enters Meena on 14 Mar, inside the month. The next new moon, 4 Apr, finds it in Meena and begins Chaitra.

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 4 Apr, with the Sun in Meena, begins Chaitra. Until then this Krishna paksha reads Chaitra here, and Phalguna in the amanta count.

A samvat year begins with Chaitra, the month whose new moon finds the Sun in Meena: 16 Mar 1980, 22:25 Sun. Since then the Sun has moved 376.9° round the stars. Vikram Samvat numbers that year 2037; Shaka Samvat numbers it 1902.