Joseph Justus Scaliger (5 August 1540 – 21 January 1609)
To link together astronomical phenomena that occur at very different times, astronomers use the Julian Day, which counts the days one by one. This way of counting days is derived from the Julian period created by Scaliger (Joseph-Juste 1540-1609). It is related to Julius Caesar's Julian calendar, because the period counts in Julian years.
From this date (-4712), astronomers count the days one by one.
For a more precise date, the Julian date is used: time passed since 1 January -4712 expressed in days and decimals.
Qlikview & Qliksense :
To convert this date to an ordinary date, the first thing to do is to extract the year :
if we take the following example: 120001
the steps for converting are :
therefore, to convert a joulian date to an ordinary date, the formula :