Julian Date and Julian Day Number Calculator Valid Over The Period From 1600 to 2200 on the Gregorian Calendar
Local Calendar Date   Year      Month    Day	Local Clock Time 00:00  to  24:00	Local Time Zone Offset From UT Negative | Positive  =  West | East UTC
Julian Date ============================================================================= Calendar Date Time Julian Date JD Num =============== ============ ================ ======= Local Date/Time LT 2025-Aug-02-Sat 07:21:40 LT 2460889.80671296 2460890 Local Time Zone TZ +00:00:00 TZ +0.00000000 Universal Time UTC 2025-Aug-02-Sat 07:21:40 UTC 2460889.80671296 2460890 Delta T Correction +00:01:09 DT +0.00080073 Terrestrial Time TT 2025-Aug-02-Sat 07:22:49 TT 2460889.80751370 2460890 TAI Correction -00:00:32.184 -0.00037250 Atomic Time TAI 2025-Aug-02-Sat 07:22:17 TAI 2460889.80714120 2460890 Astronomical JD TT 2460889.80751370 Horizons Delta T +69.183263 sec ============================================================================= ======================================== JD NUMBER TABLE Year:2025 | Month:Aug Gregorian Calendar Calendar Date JD Number Julian Date Year-Mmm-Dn-DoW JD at 12h JD at 00h ---------------- --------- ----------- 2025-Aug-01-Fri 2460889 2460888.5 2025-Aug-02-Sat 2460890 2460889.5 2025-Aug-03-Sun 2460891 2460890.5 2025-Aug-04-Mon 2460892 2460891.5 2025-Aug-05-Tue 2460893 2460892.5 2025-Aug-06-Wed 2460894 2460893.5 2025-Aug-07-Thu 2460895 2460894.5 2025-Aug-08-Fri 2460896 2460895.5 2025-Aug-09-Sat 2460897 2460896.5 2025-Aug-10-Sun 2460898 2460897.5 2025-Aug-11-Mon 2460899 2460898.5 2025-Aug-12-Tue 2460900 2460899.5 2025-Aug-13-Wed 2460901 2460900.5 2025-Aug-14-Thu 2460902 2460901.5 2025-Aug-15-Fri 2460903 2460902.5 2025-Aug-16-Sat 2460904 2460903.5 2025-Aug-17-Sun 2460905 2460904.5 2025-Aug-18-Mon 2460906 2460905.5 2025-Aug-19-Tue 2460907 2460906.5 2025-Aug-20-Wed 2460908 2460907.5 2025-Aug-21-Thu 2460909 2460908.5 2025-Aug-22-Fri 2460910 2460909.5 2025-Aug-23-Sat 2460911 2460910.5 2025-Aug-24-Sun 2460912 2460911.5 2025-Aug-25-Mon 2460913 2460912.5 2025-Aug-26-Tue 2460914 2460913.5 2025-Aug-27-Wed 2460915 2460914.5 2025-Aug-28-Thu 2460916 2460915.5 2025-Aug-29-Fri 2460917 2460916.5 2025-Aug-30-Sat 2460918 2460917.5 2025-Aug-31-Sun 2460919 2460918.5 ---------------- --------- ----------- Year-Mmm-Dn-DoW JD Number Julian Date Calendar Date JD at 12h JD at 00h ========================================
SYMBOLS, TIME SCALES AND RELATIONSHIPS LT = Local (Clock) Time TZ = Local Standard Time Zone Offset From UT (Negative|Positive = West|East) NOTE: When Daylight Saving or Summer Time is in effect, then the time zone offset is one hour less than under standard time. For example, the standard time zone offset for New York City, USA, is −5 hours when standard time is in effect but when Daylight Saving Time is in effect, the time zone offset from UT is −4 hours instead. Universal Time is always standard time. UT = Universal Time Scale = UT1 From 1600 to 1961 = UTC From 1962 onward = LT − (TZ) DT = Horizons Delta T (Could be negative or positive, depending on date.) = TT − UT TT = Terrestrial Time Scale (Used for formal astronomical computations.) = UT + (DT) = LT − (TZ) + (DT) TAI = International Atomic Time Scale = TT − 00:00:32.184 = LT - (TZ) + (DT) − 00:00:32.184 JD = Julian Date (a floating point decimal value). Contains both the complete calendar date and time of day information where the decimal fraction part indicates the time of day. JD Number = Julian Day Number (always an integer value). = Unique sequential serial number of the date on the calendar. It contains only the calendar date information. = floor(JD + 0.5) DoW = Day of Week index (0=Sun, 1=Mon, 2=Tue, 3=Wed, 4=Thu, 5=Fri, 6=Sat) = (floor(JD + 0.5) + 1) mod 7 = (JDNumber + 1) mod 7
Download This PHP 7 Program: 598 kb - Julian Date and JD Number Calculator
Program by Jay Tanner Revised: Thursday, January 01, 1970 at 12:00:00 AM UTC