Panchang in Chahārbāgh, Alborz Province, Iran Sun 16 Dec 2018

The Moon gains on the Sun about 12° a day. Each 12° of lead is one tithi: 96°–108° is the 9th, Shukla Navami. A day takes the tithi in force at its sunrise, 07:09 here. Ashtami ended at 04:13, before it. Navami ends at 05:29 Mon, when the lead reaches 108°. The lead passed 0° at the new moon of 7 Dec, so the Moon is waxing: Shukla paksha.

The night of Sat 15 Dec ran from sunset 16:54 Sat to sunrise 07:09, 14 h 15 m. Cut into 15 muhurtas of 57 m, its 14th is Brahma Muhurta, the one before the last.

Daylight here, 07:09 to 16:54, splits into 8 choghadiyas of 1 h 13 m. Their names follow a fixed order that starts from the weekday, and each name is counted good, neutral or bad.

The night here, 16:54 to 07:10 Mon, splits into 8 choghadiyas of 1 h 47 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 Bhadrapada spans 333°20′–346°40′; the Moon entered its pada 2 at 336°40′. It leaves at 01:07 Mon, for Revati.

Add the Sun's and the Moon's places among the stars: 240° + 337.4° = 577.4°, one full turn and 217.4°. Past the turn, cut into 27 parts of 13°20′, it gives the yoga: 213°20′–226°40′ is the 17th, Vyatipata. It ends at 23:46, then Variyana.

A karana is half a tithi: 6° of the Moon's lead, so the first half of Navami is Balava and the second Kaulava. Balava runs until 16:56, when the lead reaches 102°; Kaulava until 05:29 Mon.

A Hindu day runs from one sunrise to the next, not midnight to midnight. This one runs 07:09 to 07:10 Mon, so the hours after midnight still belong to Raviwara.

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: Vrishchika gives Margashirsha. The Sun enters Dhanu on 16 Dec, inside the month. The next new moon, 6 Jan, finds it in Dhanu and begins Pausha.

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 7 Dec, with the Sun in Vrishchika, began Margashirsha. This Shukla paksha reads Margashirsha in both counts.

A samvat year begins with Chaitra, the month whose new moon finds the Sun in Meena: 17 Mar 2018, 16:41 Sat. Since then the Sun has moved 267.2° round the stars. Vikram Samvat numbers that year 2075; Shaka Samvat numbers it 1940.