You may enter Calendar Date or Julian Date (Julian Day Number)
(both referred to Greenwich). Leave the cursor
in the text field which shall be your input. The six text
fields on the left side represent calendar date whereas the three
on the right side represent julian date.
The conversion is done as soon as you
hit Return or press one of the buttons.
Some important remarks apply to the conversion routines
- since 15 Oct 1582 they represent Gregorian calendar
- before 15 Oct 1582 they represent Julian Calendar;
this implies a Julian Calendar even for times when nobody knew about it
(proleptic Julian Calendar)
- there is a gap of ten days between 4 Oct 1582 and 15 Oct 1582,
meaning that the 15th of October was directly following the 4th of October
(Pope Gregor forced this in order to achieve better agreement
between the civil and the astronomical calendar)
More information about the
history of calendars is available online.
It will not matter if you enter unvalid dates such as 234 for Day,
1 for Month and 1996
for the Year. This will be treated as the 234th January of the year 1996, just meaning
the 234th day of the year. And that's the same as the 203rd February and so on.
The same applies to time values. You may leave hours and minutes empty and enter 72000 in
the textfield Second.
This will be converted to 20 hours, zero minutes and zero seconds. Go and play around with this feature.
After hitting Return you'll find correct dates anyway.
Dieter Egger, last update 2002-02-26