section_path: Structure/Day
section_name: Day
paragraph_text: Day
  
  The calendar recognises two types of day: astronomical and civil. The mean Burmese astronomical day is from midnight to midnight, and represents 1/30 of a synodic month or 23 hours, 37 minutes and 28.08 seconds. The civil day comprises two halves, the first half beginning at sunrise and the second half at sunset. In practice, four points of the astronomical and civil day (sunrise, noon, sunset, and midnight) were used as reference points. The civil day is divided into 8 baho (ဗဟို) (3 hours) or 60 nayi (နာရီ) (24 minutes), each baho equalling 7.5 nayi. In the past, a gong (မောင်း) was struck every nayi while a drum (စည်) and a large bell (ခေါင်းလောင်း) were struck to mark every baho.
  
  Although the popular usage never extended beyond baho and nayi measurements, the calendar consists of time units down to the millisecond level.
  
  Only the following are used in calendrical calculations:
  
  Therefore, modern time units can be expressed as: