Tag Archive


amateur astronomy awk bash be b[e] supergiant cartoon conference convert exoplanet fedora figaro fits fun galaxy history iraf jupiter latex linux magellanic clouds massive star matplotlib meteor mypaper ondrejov observatory optical paper peblo photometry planet pro-am pyraf python scisoft skinakas observatory small magellanic cloud smc spectroscopy starlink talk theli ubuntu university of crete video x-ray

Decimal fraction in Julian Date

Julian Day is a convenient way to count continuously days since the beginning of a specific time (noon of January 1, 4713 BC). This was proposed by Joseph Scaliger in 1583, as the beginning of the Julian Period, which epoch started when the three calendar cycles were together in their first year (4713 BC, preceding […]

Gregorian calendar date to Julian Date number

JD = (1461 x (Y + 4800 + (M – 14)/12))/4 + (367 x (M -2 -12 x ((M – 14)/12)))/12 – (3 x ((Y + 4900 + (M – 14)/12)/100))/4 + D – 32075 where JD=julian date number, Y=year, M=month, D=day of month and valid for JD≥0, date after -4713 November 23. source: Cox […]