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
2460768.5
0.849432870370
-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 03 [Thursday] Gregorian JD Number = 2460769 JD00 = 2460768.5 = JD for 00h of date Local Time = 20:23:11 = 0.849432870370 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) = 2460769.557766203703 Longitude = -76° 49' 23.915" = -76.8233097222° (W) = -05h 07m 17.594s = -5.1215539815 h ================================================================= Local Mean Sidereal Time at Longitude -76.8233097222° (W) 09h 06m 22.616s = 9.1062822800 h 136° 35' 39.24" = 136.5942342002° Local True Sidereal Time at Longitude = -76.8233097222° (W) 09h 06m 22.655s = 9.1062929570 h 136° 35' 39.82" = 136.5943943546° Greenwich Mean Sidereal Time 14h 13m 40.211s = 14.2278362615 h 213° 25' 03.158" = 213.4175439226° Greenwich True Sidereal Time 14h 13m 40.249s = 14.2278469385 h 213° 25' 03.735" = 213.4177040769° ================================================================= Applied Auxiliary Computations Time Factors Corresponding to Full Astronomical JD T = 0.252554627411 Julian centuries reckoned from J2000.0 t = 0.025255462741 Julian millennia reckoned from J2000.0 Nutations (IAU 2000B Series) +0.628" = +0.0001745578° = Nutation in ecliptical longitude +9.474" = +0.0026316403° = Nutation in ecliptical obliquity +0.038s = +0.0001601544° = Equation of the equinoxes Mean Obliquity of the Ecliptic 23° 26' 09.626" = 23.4360072547° True Obliquity of the Ecliptic 23° 26' 19.100" = 23.4386388950°
Jay Tanner - PHP Science Labs - 2025 - 1.7