Shri Siddhivinayak Vastu Jyotish Karyalaya
Brahmanas and Rig Veda define Muhurta as “muhu” (moment/immediate) + “ṛta” (order).So, it is the moment which occurs in an order every day.
Muhurta for astrological purposes of defining the quality of time is not exactly 48 minutes every day and can vary based on sunrise, sunset and local noon. This is a non-linear concept being cyclical and is also not fixed. There are 30 muhurtas in a nakshatra ahoratra (sidereal day and night reckoned from one sunrise to the next sunrise).
The period from sunrise to local noon is divided into 7½ Muhurta as is the period between local noon and sunset. In a similar manner the period from sunset to midnight and midnight to the next sunrise is divided into 7½ Muhurta each (7½ Muhurta x 4 = 30 Muhurta).
These four points of time – sunrise, local noon, sunset and midnight are the four Gayatri pada. Each of the four time span between these points measuring 7½ Muhurta is called a Prahara. So, the four (4) Prahara make a day. The eighth Muhurta spanning the last ½ Muhurta of the morning and first ½Muhurta of the afternoon is called Abhijeet Muhurta and is very auspicious as it maps into the Abhijeet nakshatra which is ruled by Hari (Narayana; hence Hari vamsa or Hari-kulesa belonging to the lineage of Hari).