In Indian culture, a day was divided into eight praharas (of three hours each) or thirty muhurtas (of 48 minutes each). In both systems, the day commences with sunrise. The timing of the two systems coincides only at sunrise and sunset (four praharas coincide with fifteen muhurtas at the twelve-hour, or 720-minute, point).

Now as we are discussing about prayers, lets keep the muhurats aside.

The concept of prahar originated where the lengths of the day and night were based on actual, observable sunrise and sunset.

The four praharas of the day start at sunrise, and the four praharas of the night at sunset.

If the location is near the equator, where day and night are the same length year round, the praharas of the day and the praharas of the night will be of equal length (three hours each).

At the Equator where 6:00 am is referred as the theoretical the time of sunrise.

The four Prahars of the day corresponds to-

Pehla Prahar 6:00 A.M. to 9 A.M is called Purvaanha

Doosra Prahar 9:00 A.M. to Noon is called Madhyaanha

Teesra Prahar Noon to 3:00 P.M. is called Aparaanha

Choutha Prahar 3:00 P.M. to 6:00 P.M. is called Saayankala

The four Prahars of the night corresponds to-

Pehla Prahar 6:00 P.M. to 9 P.M is called Pradosha

Doosra Prahar 9:00 P.M. to Midnight is called Nishitha

Teesra Prahar Midnight to 3:00 A.M. is called Triyaamaa

Choutha Prahar 3:00 A.M. to 6:00 A.M. is called Ushaa

In other regions, where the relative length of day and night varies according to the season, the praharas of the day will be longer or shorter than the praharas of the night.

During the summer, when the days are longer than the nights, the praharas of the day will be longer than the praharas of the night, and vice versa during the winter.

In Indian classical music, some Ragas are prescribed to be performed at a particular prahara to maximize their aesthetic effects. Sangita-Makaranda is an ancient Indian text that warns musicians against playing ragas at the incorrect time of day. Traditionally, disastrous consequences are to be expected.

Coming to Raga Darbari Kanada. It can cure insomnia and induce sleep. It belongs to the Asavari Thaat.

Though most of the ragas in Asavari thaat are performed in the late morning hours. Darbari is sung in the Night prahars as it is a grave raga.