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
2461320.5
0.029930555556
-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 = +76 sec = +00h 01m 16s
Double-Click Within Text Area to Select ALL Text
SIDEREAL TIME FOR GIVEN DATE, TIME AND LONGITUDE Local Date = 2026 Oct 07 [Wednesday] Gregorian JD Number = 2461321 JD00 = 2461320.5 = JD for 00h of date Local Time = 00:43:06 = 0.029930555556 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) = 2461320.738263888889 Longitude = -76° 49' 23.915" = -76.8233097222° (W) = -05h 07m 17.594s = -5.1215539815 h ================================================================= Local Mean Sidereal Time at Longitude -76.8233097222° (W) 01h 39m 22.322s = 1.6562006489 h 24° 50' 34.84" = 24.8430097331° Local True Sidereal Time at Longitude = -76.8233097222° (W) 01h 39m 22.848s = 1.6563465540 h 24° 50' 42.71" = 24.8451983094° Greenwich Mean Sidereal Time 06h 46m 39.917s = 6.7777546304 h 101° 39' 58.750" = 101.6663194555° Greenwich True Sidereal Time 06h 46m 40.442s = 6.7779005355 h 101° 40' 06.629" = 101.6685080318° ================================================================= Applied Auxiliary Computations Time Factors Corresponding to Full Astronomical JD T = 0.267645127005 Julian centuries reckoned from J2000.0 t = 0.026764512700 Julian millennia reckoned from J2000.0 Circular Trig Functions of Given Longitude Longitude = -76.8233097222° (W) sin(Lon) = -0.973671722605411 cos(Lon) = +0.227954768756023 tan(Lon) = -4.271337370649689 Nutations (IAU 2000B Series) +8.587" = +0.0023853946° = Nutation in ecliptical longitude +8.289" = +0.0023024820° = Nutation in ecliptical obliquity +0.525s = +0.0021885763° = Equation of the equinoxes Mean Ecliptic Obliquity 23° 26' 08.920" = 23.4358110406° Nutation in Obliquity +8.289" = +0.0023024820° True Ecliptic Obliquity 23° 26' 17.209" = 23.4381135226°
Jay Tanner - PHP Science Labs - 2026 - 1.7