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
2460741.5
0.108263888889
-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 Mar 07 [Friday] Gregorian JD Number = 2460742 JD00 = 2460741.5 = JD for 00h of date Local Time = 02:35:54 = 0.108263888889 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) = 2460741.816597222222 Longitude = -76° 49' 23.915" = -76.8233097222° (W) = -05h 07m 17.594s = -5.1215539815 h ================================================================= Local Mean Sidereal Time at Longitude -76.8233097222° (W) 13h 29m 43.294s = 13.4953593731 h 202° 25' 49.41" = 202.4303905969° Local True Sidereal Time at Longitude = -76.8233097222° (W) 13h 29m 43.375s = 13.4953818444 h 202° 25' 50.62" = 202.4307276656° Greenwich Mean Sidereal Time 18h 37m 00.888s = 18.6169133546 h 279° 15' 13.321" = 279.2537003192° Greenwich True Sidereal Time 18h 37m 00.969s = 18.6169358259 h 279° 15' 14.535" = 279.2540373879° ================================================================= Applied Auxiliary Computations Time Factors Corresponding to Full Astronomical JD T = 0.251795115598 Julian centuries reckoned from J2000.0 t = 0.025179511559 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) +1.323" = +0.0003673828° = Nutation in ecliptical longitude +9.506" = +0.0026405939° = Nutation in ecliptical obliquity +0.081s = +0.0003370687° = Equation of the equinoxes Mean Ecliptic Obliquity 23° 26' 09.662" = 23.4360171303° Nutation in Obliquity +9.506" = +0.0026405939° True Ecliptic Obliquity 23° 26' 19.168" = 23.4386577241°
Jay Tanner - PHP Science Labs - 2025 - 1.7