Panchang in Codcod, Western Visayas, Philippines Sat 13 Sep 1980

Ganesha’s puja is done at madhyahna, the middle fifth of the day. Chaturthi runs from 01:08 on Sat 13 Sep to 03:37 on Sun 14 Sep, so only Saturday’s madhyahna (10:29–12:56) falls within it.

Ganesh Chaturthi: every date in Codcod

The Moon gains on the Sun about 12° a day. Each 12° of lead is one tithi: 36°–48° is the 4th, Shukla Chaturthi. A day takes the tithi in force at its sunrise, 05:36 here. Tritiya ended at 01:08, before it. Chaturthi ends at 03:37 Sun, when the lead reaches 48°. The lead passed 0° at the new moon of 9 Sep, so the Moon is waxing: Shukla paksha.

The night of Fri 12 Sep ran from sunset 17:49 Fri to sunrise 05:36, 11 h 47 m. Cut into 15 muhurtas of 47 m, its 14th is Brahma Muhurta, the one before the last.

Daylight here, 05:36 to 17:49, splits into 8 choghadiyas of 1 h 31 m. Their names follow a fixed order that starts from the weekday, and each name is counted good, neutral or bad.

The night here, 17:49 to 05:36 Sun, splits into 8 choghadiyas of 1 h 28 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′. Chitra spans 173°20′–186°40′; the Moon entered its pada 4 at 183°20′. It leaves at 09:36, for Swati.

Add the Sun's and the Moon's places among the stars: 146.7° + 184.7° = 331.4°. The sum, cut into 27 parts of 13°20′, gives the yoga: 320°00′–333°20′ is the 25th, Brahma. It ends at 09:17, then Indra.

A karana is half a tithi: 6° of the Moon's lead, so the first half of Chaturthi is Vanija and the second Vishti. Vanija runs until 14:23, when the lead reaches 42°; Vishti until 03:37 Sun.

A Hindu day runs from one sunrise to the next, not midnight to midnight. This one runs 05:36 to 05:36 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: Simha gives Bhadrapada. The Sun enters Kanya on 16 Sep, inside the month. The next new moon, 9 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 9 Sep, with the Sun in Simha, began Bhadrapada. This Shukla paksha reads Bhadrapada in both counts.

A samvat year begins with Chaitra, the month whose new moon finds the Sun in Meena: 17 Mar 1980, 02:55 Mon. Since then the Sun has moved 173.9° round the stars. Vikram Samvat numbers that year 2037; Shaka Samvat numbers it 1902.