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
2461155.5
0.436504629630
-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 = 2026 Apr 25 [Saturday] Gregorian JD Number = 2461156 JD00 = 2461155.5 = JD for 00h of date Local Time = 10:28:34 = 0.436504629630 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) = 2461156.144837962963 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 35m 54.864s = 0.5985732491 h 08° 58' 42.95" = 8.9785987372° Local True Sidereal Time at Longitude = -76.8233097222° (W) 00h 35m 55.235s = 0.5986763018 h 08° 58' 48.52" = 8.9801445265° Greenwich Mean Sidereal Time 05h 43m 12.458s = 5.7201272306 h 85° 48' 06.870" = 85.8019084595° Greenwich True Sidereal Time 05h 43m 12.829s = 5.7202302833 h 85° 48' 12.435" = 85.8034542489° ================================================================= Applied Auxiliary Computations Time Factors Corresponding to Full Astronomical JD T = 0.263138804598 Julian centuries reckoned from J2000.0 t = 0.026313880459 Julian millennia reckoned from J2000.0 Nutations (IAU 2000B Series) +6.065" = +0.0016848038° = Nutation in ecliptical longitude +8.588" = +0.0023855440° = Nutation in ecliptical obliquity +0.371s = +0.0015457894° = Equation of the equinoxes Mean Obliquity of the Ecliptic 23° 26' 09.131" = 23.4358696340° True Obliquity of the Ecliptic 23° 26' 17.719" = 23.4382551780°
Jay Tanner - PHP Science Labs - 2026 - 1.7