Panchang in Chahārbāgh, Alborz Province, Iran Fri 15 Apr 2016

Rama’s birth is celebrated at madhyahna, the middle fifth of the day. Navami runs from 20:29 on Thu 14 Apr to 21:03 on Fri 15 Apr, so only Friday’s madhyahna (11:48–14:25) falls within it. Every reading takes that day.

Rama Navami: every date in Chahārbāgh

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, 06:33 here. Ashtami ended at 20:29 Thu, before it. Navami ends at 21:03, when the lead reaches 108°. The lead passed 0° at the new moon of 7 Apr, so the Moon is waxing: Shukla paksha.

The night of Thu 14 Apr ran from sunset 19:39 Thu to sunrise 06:33, 10 h 54 m. Cut into 15 muhurtas of 43 m, its 14th is Brahma Muhurta, the one before the last.

Daylight here, 06:33 to 19:40, splits into 8 choghadiyas of 1 h 38 m. Their names follow a fixed order that starts from the weekday, and each name is counted good, neutral or bad.

The night here, 19:40 to 06:32 Sat, splits into 8 choghadiyas of 1 h 21 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′. Pushya spans 93°20′–106°40′; the Moon entered its pada 3 at 100°. It leaves at 14:35, for Ashlesha.

Add the Sun's and the Moon's places among the stars: 1.5° + 102.4° = 103.9°. The sum, cut into 27 parts of 13°20′, gives the yoga: 93°20′–106°40′ is the 8th, Dhriti. It ends at 11:26, then Shula.

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 08:40, when the lead reaches 102°; Kaulava until 21:03.

A Hindu day runs from one sunrise to the next, not midnight to midnight. This one runs 06:33 to 06:32 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: Meena gives Chaitra. The Sun enters Mesha on 13 Apr, inside the month. The next new moon, 6 May, finds it in Mesha and begins Vaishakha.

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 Apr, with the Sun in Meena, began Chaitra. This Shukla paksha reads Chaitra in both counts.

A samvat year begins with Chaitra, the month whose new moon finds the Sun in Meena: 7 Apr 2016, 15:53 Thu. Since then the Sun has moved 7.5° round the stars. Vikram Samvat numbers that year 2073; Shaka Samvat numbers it 1938.