What is Do Ghati Muhurat?
A ghati is a Vedic unit of time of about 24 minutes, so do ghati ("two ghatis") is roughly 48 minutes. In this system the day from sunrise to sunset is divided into 15 muhurtas and the night from sunset to the next sunrise into another 15 — thirty muhurtas over the full ahoratra, each about two ghatis long. Every muhurta has a fixed classical name and a traditional nature, auspicious or inauspicious.
The day and night muhurtas
The fifteen day muhurtas run in order from sunrise — Rudra, Ahi, Mitra, Pitri, Vasu, Vara, Vishvedeva, Abhijit, Sutamukhi, Puruhuta, Vahini, Naktanakara, Varuna, Aryaman and Bhaga. The eighth, Abhijit, falls at midday and is the most celebrated — auspicious for almost any work (though it is avoided on Wednesday). The fifteen night muhurtas run from sunset — Girish, Ajapada, Ahirbudhnya, Pushan, Ashwini, Yama, Agni, Vidhatri, Kanda, Aditi, Jiva, Vishnu, Dyuman, Brahma and Samudram. The Brahma muhurta near dawn is especially auspicious for worship and study.
How the timings are set
Because the day and night are each split into fifteen equal parts, the length of a muhurta depends on the day/night length at your place and date — a day muhurta is longer in summer, shorter in winter. Set your location above so the times match your city.
Using Do Ghati Muhurat
Pick an auspicious muhurta clear of the day's inauspicious windows — Rahu Kaal, Yamaganda and Gulika — and read it together with the day's Panchang, the Choghadiya and Hora.