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
2461073.5
0.009606481481
-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 Feb 02 [Monday] Gregorian JD Number = 2461074 JD00 = 2461073.5 = JD for 00h of date Local Time = 00:13:50 = 0.009606481481 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) = 2461073.717939814814 Longitude = -76° 49' 23.915" = -76.8233097222° (W) = -05h 07m 17.594s = -5.1215539815 h ================================================================= Local Mean Sidereal Time at Longitude -76.8233097222° (W) 08h 56m 12.338s = 8.9367606640 h 134° 03' 05.08" = 134.0514099593° Local True Sidereal Time at Longitude = -76.8233097222° (W) 08h 56m 12.790s = 8.9368860134 h 134° 03' 11.85" = 134.0532902004° Greenwich Mean Sidereal Time 14h 03m 29.933s = 14.0583146454 h 210° 52' 28.991" = 210.8747196817° Greenwich True Sidereal Time 14h 03m 30.384s = 14.0584399948 h 210° 52' 35.760" = 210.8765999227° ================================================================= Applied Auxiliary Computations Time Factors Corresponding to Full Astronomical JD T = 0.260882079118 Julian centuries reckoned from J2000.0 t = 0.026088207911 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) +7.378" = +0.0020493335° = Nutation in ecliptical longitude +8.589" = +0.0023858565° = Nutation in ecliptical obliquity +0.451s = +0.0018802410° = Equation of the equinoxes Mean Ecliptic Obliquity 23° 26' 09.236" = 23.4358989771° Nutation in Obliquity +8.589" = +0.0023858565° True Ecliptic Obliquity 23° 26' 17.825" = 23.4382848335°
Jay Tanner - PHP Science Labs - 2026 - 1.7