MJDate is a Windows 95/98/NT program to display a monthly calendar showing the Day of Year (DOY)
and Modified Julian Date (MJD).  The MJD can be used as a timetag for phase or frequency data.
The calendar also shows the GPS week #s for the selected month.  It is limited to between
January 1900 and December 2099, a range of about +/- 100 years from the present time.
The MJD is valid over this entire range (15020-88068), and it has been checked for Y2K compliance.  The GPS week # display starts at January 1980.  The current date is not displayed after January 18, 2038 because of C time function overflow, and the current month defaults to December, 1969.  Other operating system date limits may exist on some computers.

The Modified Julian Date (MJD) is based on the astronomical Julian Date, the # of days since noon
on January 1, 4713 BC.  The MJD is the Julian Date - 2,4000,000.5; it starts at midnight on
November 17, 1858.  MJD 50,000 was on October 10, 1995.

The GPS week number is a time scale used by the Global Positioning System.  It is a modulo 1024
number having an origin at 0000 UTC on January 6, 1980.  The first GPS week rollover was on
August 22, 1999 (MJD 51412).

To install MJDate, simply execute a:\setup from Run in Windows Start.

Please see the on-line Help file for more information about operating the MJDate program.     

