Today September 2, is a significant date in the history of Gregorian Calendar, which is being followed by most of the Countries for official purposes. It was on Wednesday, September 2,1752, Great Britain and its Colonies advanced 12 days in the Calendars by The British Calendar Act, 1751, to keep in pace with other Countries in Europe. Consequently changed from Julian Calendar, named after Julius Caesar, to Gregorian Calendar, named after Pope Gregory XIII, who adopted this system to correct errors in Julian Calendar. Thus next day Thursday was changed to September 14, 1752, skipping 12 days overnight. Even though Gregorian Calendar corrected the number of days per year as 365.2425, it is still perceived not accurate. Many Countries follow their own traditional systems of calendars basing on Solar or Lunar Cycle. Calendar is an interesting subject which mixes Scientific observation of Astronomy and Astrological beliefs.