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
0.456215277778
-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 = 10:56:57 = 0.456215277778 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) = 2460769.164548611111 Longitude = -76° 49' 23.915" = -76.8233097222° (W) = -05h 07m 17.594s = -5.1215539815 h ================================================================= Local Mean Sidereal Time at Longitude -76.8233097222° (W) 23h 38m 35.598s = 23.6432218009 h 354° 38' 53.98" = 354.6483270139° Local True Sidereal Time at Longitude = -76.8233097222° (W) 23h 38m 35.634s = 23.6432316829 h 354° 38' 54.51" = 354.6484752439° Greenwich Mean Sidereal Time 04h 45m 53.193s = 4.7647757824 h 71° 28' 17.892" = 71.4716367363° Greenwich True Sidereal Time 04h 45m 53.228s = 4.7647856644 h 71° 28' 18.426" = 71.4717849663° ================================================================= Applied Auxiliary Computations Time Factors Corresponding to Full Astronomical JD T = 0.252543861700 Julian centuries reckoned from J2000.0 t = 0.025254386170 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) +0.582" = +0.0001615609° = Nutation in ecliptical longitude +9.478" = +0.0026329022° = Nutation in ecliptical obliquity +0.036s = +0.0001482300° = Equation of the equinoxes Mean Ecliptic Obliquity 23° 26' 09.627" = 23.4360073947° Nutation in Obliquity +9.478" = +0.0026329022° True Ecliptic Obliquity 23° 26' 19.105" = 23.4386402969°
Jay Tanner - PHP Science Labs - 2025 - 1.7