Difference Between Dates and Optional Times
Start Date:   ±Y  M  D Start Time:   H M S
Calendar Mode:   Julian            Gregorian
End Date:   ±Y  M  D End Time:   H M S 
Calendar Mode = Gregorian


Start Date/Time   = 2019 March 21 Thu 12:00:00.000
Julian Date       = 2458564
Julian Day Number = 2458564

————————————————————
2019           March

Su Mo Tu We Th Fr Sa
                1  2 
 3  4  5  6  7  8  9 
10 11 12 13 14 15 16 
17 18 19 20 21 22 23 
24 25 26 27 28 29 30 
31
————————————————————


*******************************************************


End Date/Time     = 2019 March 21 Thu 12:00:00.000
Julian Date       = 2458564
Julian Day Number = 2458564

————————————————————
2019           March

Su Mo Tu We Th Fr Sa
                1  2 
 3  4  5  6  7  8  9 
10 11 12 13 14 15 16 
17 18 19 20 21 22 23 
24 25 26 27 28 29 30 
31
————————————————————

DIFFERENCE BETWEEN DATES AND TIMES
= (JD2 − JD1) = 0 d
= 0 Gregorian yr
=  0d  00h 00m 00s