Astronomical Julian Date and JD Number Table Calculator Range: BC 9999-Mar-22-Fri  to  AD 9999-Dec-30-Thu
Start Date  BC|AD  Year-Month-Day			Stop Date  BC|AD  Year-Month-Day
Double-Click Within Text Area to Select ALL Text === ERROR === At least one of the calendar date arguments is invalid or the table may be too large to print. Carefully check the date and the general rules and error resolution tips below. ------------------------- VALID CALENDAR DATE RANGE BC 9999-Mar-22 to AD 9999-Dec-30 The month can be any 3-letter English month name abbreviation or a month number from 1 to 12. Abbreviations are NOT case sensitive but they MUST consist of the correct 3 letters from 'Jan' to 'Dec'. Make sure month day is within the proper 28 to 31-day range for the given month. Feb 29th in a non-leap year will cause an error. May 34th would cause an error - no such date. Etc. -------------------------------- JULIAN/GREGORIAN TRANSITION NOTE Technically, dates from 1582-Oct-05-Fri to 1582-Oct-14-Sun, do not exist. They were dropped from the calendar during the transition from the old Julian calendar to the modern Gregorian calendar used today and the leap year rule was also changed to prevent the same error from recurring. ------------------- TO GENERATE A TABLE The Stop Date MUST BE LATER than the Start Date or an error will result. An error may result if the table is much too large to print. However, the generated table can still span many, many years longer than a human lifetime - over 200 years. One could make a JD Number table for every day of a person's lifetime and far beyond.
===================================================== SOME GENERAL PROGRAM INFORMATION This program handles ancient dates prior to BC 4713 which produces negative Julian dates and Julian day numbers. Both the Julian and Gregorian calendars are applied with the Julian calendar being used for all dates up to AD 1582-Oct-04-Thu. The modern Gregorian calendar calendar is used for all dates after that up to the current date and all future dates. -------------------------------------------------- THE DIFFERENCE JULIAN DATES AND JULIAN DAY NUMBERS The JULIAN DATE contains both calendar date and the time of day information. Any fractional part of the Julian Date indicates the time of day. The JULIAN DAY NUMBER is always an integer value and only contains the calendar date information. It does NOT tell us the time of day. It is simply the exact count of calendar days since the mathematical origin of the calendar system or a unique serial number for every given date on the calendar system. The difference between two Julian Day numbers equates to the exact number of calendar days between the two corresponding dates, taking into account all leap years between the dates. The default startup date is the current date (UTC). Any interface date values left blank will be filled by the current default values from the system clock. A cookie is used to store the date arguments between calls. ===================================================== Program built around the NASA/JPL Horizons API v1.2
Program by Jay Tanner Revised: Thursday, January 01, 1970 at 12:00:00 AM UTC