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-Sep-17-Wed 08:16:04 LT 2460935.84449074 2460936 Local Time Zone TZ +00:00:00 TZ +0.00000000 Universal Time UTC 2025-Sep-17-Wed 08:16:04 UTC 2460935.84449074 2460936 Delta T Correction +00:01:09 DT +0.00080072 Terrestrial Time TT 2025-Sep-17-Wed 08:17:13 TT 2460935.84529146 2460936 TAI Correction -00:00:32.184 -0.00037250 Atomic Time TAI 2025-Sep-17-Wed 08:16:41 TAI 2460935.84491896 2460936 Astronomical JD TT 2460935.84529146 Horizons Delta T +69.182451 sec ============================================================================= ======================================== JD NUMBER TABLE Year:2025 | Month:Sep Gregorian Calendar Calendar Date JD Number Julian Date Year-Mmm-Dn-DoW JD at 12h JD at 00h ---------------- --------- ----------- 2025-Sep-01-Mon 2460920 2460919.5 2025-Sep-02-Tue 2460921 2460920.5 2025-Sep-03-Wed 2460922 2460921.5 2025-Sep-04-Thu 2460923 2460922.5 2025-Sep-05-Fri 2460924 2460923.5 2025-Sep-06-Sat 2460925 2460924.5 2025-Sep-07-Sun 2460926 2460925.5 2025-Sep-08-Mon 2460927 2460926.5 2025-Sep-09-Tue 2460928 2460927.5 2025-Sep-10-Wed 2460929 2460928.5 2025-Sep-11-Thu 2460930 2460929.5 2025-Sep-12-Fri 2460931 2460930.5 2025-Sep-13-Sat 2460932 2460931.5 2025-Sep-14-Sun 2460933 2460932.5 2025-Sep-15-Mon 2460934 2460933.5 2025-Sep-16-Tue 2460935 2460934.5 2025-Sep-17-Wed 2460936 2460935.5 2025-Sep-18-Thu 2460937 2460936.5 2025-Sep-19-Fri 2460938 2460937.5 2025-Sep-20-Sat 2460939 2460938.5 2025-Sep-21-Sun 2460940 2460939.5 2025-Sep-22-Mon 2460941 2460940.5 2025-Sep-23-Tue 2460942 2460941.5 2025-Sep-24-Wed 2460943 2460942.5 2025-Sep-25-Thu 2460944 2460943.5 2025-Sep-26-Fri 2460945 2460944.5 2025-Sep-27-Sat 2460946 2460945.5 2025-Sep-28-Sun 2460947 2460946.5 2025-Sep-29-Mon 2460948 2460947.5 2025-Sep-30-Tue 2460949 2460948.5 ---------------- --------- ----------- 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