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 ( ) (3 hours) or 60 nayi ( ) (24 minutes), each baho equalling 7.5 nayi. In the past, a gong ( ) was struck every nayi while a drum ( ) and a large bell ( ) 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: Week The civil week consists of seven days. It was also customary to denote the day of the week by its preassigned numerical value between zero and six. The names Taninganwe (Sunday) and Taninla (Monday) are derived from Old Burmese but the rest from Sanskrit. Month The calendar recognises two types of months: synodic month and sidereal month. The Synodic months are used to compose the years while the 27 lunar sidereal days ( ; from Sanskrit nakshatra), alongside the 12 signs of the zodiac, are used for astrological calculations. (The calendar also recognises a solar month called Thuriya Matha, which is defined as 1/12th of a year. But the solar month varies by the type of year such as tropical year, sidereal year, etc.) The days of the month are counted in two halves, waxing ( ) and waning ( ). The 15th of the waxing ( ) is the civil full moon day. The civil new moon day ( ) is the last day of the month (14th or 15th waning). The mean and real (true) New Moons rarely coincide. The mean New Moon often precedes the real New Moon. As the Synodic lunar month is approximately 29.5 days, the calendar uses alternating months of 29 and 30 days. The 29-day months are called yet-ma-son la (), and the 30-day months are called yet-son la (). Unlike in other Southeast Asian traditions, the Burmese calendar uses Burmese names for the month names. Although the names sound foreign in origin to modern Burmese ears, all but three are derived from Old Burmese. The three exceptions—Mleta/Myweta (), Nanka (), Thantu ()—which all fall