January 0
From Wikipedia, the free encyclopedia
January 0 refers to the day before January 1 in an annual ephemeris. It keeps the date in the year for which the ephemeris was published, thus avoiding any reference to the previous year, even though it is the same day as December 31 of the previous year. In a similar way March 0 refers to the day before March 1, keeping it in March without mentioning that it is the last day of February.
[edit] In other fields
In Microsoft Excel, the day 0 of the 1900 date format is January 0, 1900. However, as the fact that 1900 was not a leap year in the Gregorian calendar is ignored, it actually corresponds to December 30, 1899.
