Sidereal Time Calculator For Any Date, Time and Longitude
PHP Program by Jay Tanner
Local Date
±
Y M D (Neg=BC)
Local Time
HH MM SS (00 to 24h)
Local Time Zone Offset
HH MM (Neg/Pos = W/E)
ΔT (Delta T)
±
HMS
UT
2460929.5
0.038738425926
-0.208333333333
+0.000000000000
Calendar Mode:
Julian
Gregorian
Longitude:
±Deg.ddd or ±D M S (Neg=W)
-76.8233097222
IMPORTANT:
Make sure that the local time, time zone and longitude are correctly matched for the location.
Optional NASA Polynomial ΔT estimate = +75 sec = +00h 01m 15s
Double-Click Within Text Area to Select ALL Text
SIDEREAL TIME FOR GIVEN DATE, TIME AND LONGITUDE Local Date = 2025 Sep 11 [Thursday] Gregorian JD Number = 2460930 JD00 = 2460929.5 = JD for 00h of date Local Time = 00:55:47 = 0.038738425926 day T Zone Diff = -05:00 = -0.208333333333 day Delta T = +00:00:00 = +0.000000000000 day Astronomical Julian Date: JDTT = JDNum - 0.5 + LTFrac - (TZFrac) + (dTFrac) = 2460929.747071759259 Longitude = -76° 49' 23.915" = -76.8233097222° (W) = -05h 07m 17.594s = -5.1215539815 h ================================================================= Local Mean Sidereal Time at Longitude -76.8233097222° (W) 00h 10m 32.257s = 0.1756268127 h 02° 38' 03.85" = 2.6344021908° Local True Sidereal Time at Longitude = -76.8233097222° (W) 00h 10m 32.473s = 0.1756870672 h 02° 38' 07.10" = 2.6353060086° Greenwich Mean Sidereal Time 05h 17m 49.851s = 5.2971807942 h 79° 27' 27.763" = 79.4577119132° Greenwich True Sidereal Time 05h 17m 50.068s = 5.2972410487 h 79° 27' 31.017" = 79.4586157309° ================================================================= Applied Auxiliary Computations Time Factors Corresponding to Full Astronomical JD T = 0.256940371574 Julian centuries reckoned from J2000.0 t = 0.025694037157 Julian millennia reckoned from J2000.0 Nutations (IAU 2000B Series) +3.546" = +0.0009851015° = Nutation in ecliptical longitude +9.479" = +0.0026331732° = Nutation in ecliptical obliquity +0.217s = +0.0009038178° = Equation of the equinoxes Mean Obliquity of the Ecliptic 23° 26' 09.421" = 23.4359502291° True Obliquity of the Ecliptic 23° 26' 18.900" = 23.4385834023°
Jay Tanner - PHP Science Labs - 2025 - 1.7