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
2460789.5
0.830717592593
-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 Apr 24 [Thursday] Gregorian JD Number = 2460790 JD00 = 2460789.5 = JD for 00h of date Local Time = 19:56:14 = 0.830717592593 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) = 2460790.539050925926 Longitude = -76° 49' 23.915" = -76.8233097222° (W) = -05h 07m 17.594s = -5.1215539815 h ================================================================= Local Mean Sidereal Time at Longitude -76.8233097222° (W) 10h 02m 08.852s = 10.0357921560 h 150° 32' 12.78" = 150.5368823400° Local True Sidereal Time at Longitude = -76.8233097222° (W) 10h 02m 08.865s = 10.0357958939 h 150° 32' 12.98" = 150.5369384089° Greenwich Mean Sidereal Time 15h 09m 26.446s = 15.1573461375 h 227° 21' 36.691" = 227.3601920623° Greenwich True Sidereal Time 15h 09m 26.460s = 15.1573498754 h 227° 21' 36.893" = 227.3602481312° ================================================================= Applied Auxiliary Computations Time Factors Corresponding to Full Astronomical JD T = 0.253129063680 Julian centuries reckoned from J2000.0 t = 0.025312906368 Julian millennia reckoned from J2000.0 Nutations (IAU 2000B Series) +0.220" = +0.0000611114° = Nutation in ecliptical longitude +9.409" = +0.0026136626° = Nutation in ecliptical obliquity +0.013s = +0.0000560689° = Equation of the equinoxes Mean Obliquity of the Ecliptic 23° 26' 09.599" = 23.4359997856° True Obliquity of the Ecliptic 23° 26' 19.008" = 23.4386134482°
Jay Tanner - PHP Science Labs - 2025 - 1.7