Nepali Calendar - Bikram Sambat (B.S.) Introduction, History and how it works

Every year on the 1st of Baisakh we celebrate a new year in Nepal. This is based on Bikram Sambat (B.S.) calendar. But, there is a lot we may not know about the Sambat we are accepting. There are various Sambat all around the world. In Nepal alone, we have several Sambat like Nepal Sambat (started in 879 A.D. during the reign of King Raghav Dev), Yalambar Sambat (after the name of first Kirant king Yalambar), Shaka Sambat (started in 78 B.C.; same names of months as in B.S. and only difference is only in the beginning of the month), etc. 

A.D. is a world-recognized Sambat based on Gregorian Calendar. However, B.S. has some special features over A.D. The most noticeable is B.S. is ahead 56.7 years than A.D. The other main difference between these two calendars is that A.D. is solar-based Sambat while B.S. is solar and lunar-based Sambat that means A.D. just takes reference of earth movement around solar for measurement of time while B.S. takes reference of both solar and lunar movement and speed. Simple to hear but complex, to under these required well knowledge of mathmatics, geography lines, and astronomy. 

Happy New Year 2078 to all

Bikram Sambat's abbreviation B.S. is the widely used official calendar of Nepal (Nepal Sambat also received the status of the official calendar of Nepal in 2007 but not in wide use as Bikram Sambat is widely used). Historically, it's used all over the Indian subcontinent. Bikram Sambat was founded by Tuar Rajput emperor Vikramaditya in 56 B.C. Thus, Bikram Sambat is 56/57 years ahead of Gregorian Calendar (Anno Domini, A.D.). In Nepal, the Rana dynasty made the Bikram Sambat the official calendar in 1901 AD, which is in 1958 B.S. That doesn't mean that Bikram Sambat was not used in Nepal before that period. Many historical scripts found in Nepal proofs its used since far before. 

How Bikram Sambat Calendar works?

In our house, there at least a Bikram Sambat Calendar lies in the wall. That includes tithi, paschya, etc. various information provided. But the meaning of these may have known by few, many remain unknown about this information. Tithi equivalent to lunar day, which is the time taken to make a 12-degree longitudinal angle between sun and moon. 15 tithi makes 1 paschya. There are two paschya, they are Krishna paschya and Sukla paschya. Two paschya makes 1 mas (~month). In 1 mas there are 29.5 tithis. 2 mas makes 1 ritu (~ season, 6 in year). 2 ritu make 1 aayan and 2 aayan makes 1 barsha (year). Each year starts when the sun enters into Mesh Rasi. Rasi is not only suprising imaginations each 12 Rasi names are equivalent to conic lines at a different degree from the equators. 

These all knowledge may have raised how accurate, scientific, calendar was prepared in our ancient culture, civilization.