- How old am I:
- I am still in my teens
- Body type:
- My body type is skinny
- I prefer to listen:
- My hobbies:
- Mountain climbing
There are several variations. A date in this format may include a 4-digit year yyyy or a two-digit year yy and the day may or may not be padded with zeros to always use 3 digits. For example, for the date January 21,you might see:.
This is the Julian Day for the beginning of the date in question at 0 hours, Greenwich time.
Note that this always gives you a half day extra. That is because the Julian Day begins at noonGreenwich time.
This is convenient for astronomers who until recently only observed at nightbut it is confusing. Example: If the date is October 15.
To convert a Julian Day to a Gregorian date, assume that it is for 0 hours, Greenwich time so that it ends in 0. Do the following calculations, again dropping the fractional part of all multiplicatons and divisions. Note: This method will not give dates accurately on the Gregorian Proleptic Calendar, i.
Thanks to a correspondent, Bo Du, for some ideas that have improved this calculation. Check your result by calculating the date of your birthday from the Julian Day .
These calculations are useful also when converting between the Gregorian and Julian calendars e. This method even works for dates prior to and correctly gives years prior to the Common Era as negative years with year 0 corresponding to 1 BCE, year -1 corresponding to 2 BCE, etc.
However, it does not work with negative Julian Day s and does not work when going to the Gregorian calendar for years before CE. Or, you can put in a Julian Day and it will compute the calendar date. Have fun!