Dhanu (month) followed by the solar month of Makara. The Dhanus month is called "Margali" in the Tamil Hindu calendar. The ancient and medieval era Sanskrit texts of India vary in their calculations about the duration of Dhanus, just like they do with other months. For example, the "Surya Siddhanta" calculates the duration of Vrschika to be 29 days, 7 hours, 37 minutes and 36 seconds. In contrast, the "Arya Siddhanta" calculates the duration of the Vrschika month to be 29 days, 8 hours, 24 minutes and 48 seconds. Dhanu is also an astrological sign in Indian horoscope systems, corresponding to Sagittarius
History of mathematics the Roman Kingdom and included 356 days plus a leap year every other year. In contrast, the lunar calendar of the Republican era contained 355 days, roughly ten-and-one-fourth days shorter than the solar year, a discrepancy that was solved by adding an extra month into the calendar after the 23rd of February. This calendar was supplanted by the Julian calendar, a solar calendar organized by Julius Caesar (100–44 BC) and devised by Sosigenes of Alexandria to include a leap day every four years in a 365-day cycle. This calendar, which contained an error of 11 minutes and 14 seconds, was