In his book "Outlines of Astronomy", first published in 1849, the astronomer John Herschel added the counting of days elapsed from the beginning of the Julian Period:The period thus arising of 7980 Julian years, is called the Julian period, and it has been found so useful, that the most competent authorities have not hesitated to declare that, through its employment, light and order were first introduced into chronology.
In his book Outlines of Astronomy , first published in 1849, the astronomer John Herschel wrote: در کتاب خود به تشریح نجوم، اول 1849 منتشر شده در، ستاره شناس جان هرشل نوشت :Astronomers adopted Herschel's Julian Days in the late nineteenth century, but used the meridian of Greenwich instead of Alexandria, after the former was adopted as the Prime Meridian after the International Meridian Conference in Washington in 1884.