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
2460832.5
0.384166666667
-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 Jun 06 [Friday] Gregorian JD Number = 2460833 JD00 = 2460832.5 = JD for 00h of date Local Time = 09:13:12 = 0.384166666667 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) = 2460833.0925 Longitude = -76° 49' 23.915" = -76.8233097222° (W) = -05h 07m 17.594s = -5.1215539815 h ================================================================= Local Mean Sidereal Time at Longitude -76.8233097222° (W) 02h 06m 53.099s = 2.1147496097 h 31° 43' 16.48" = 31.7212441461° Local True Sidereal Time at Longitude = -76.8233097222° (W) 02h 06m 53.179s = 2.1147719066 h 31° 43' 17.68" = 31.7215785994° Greenwich Mean Sidereal Time 07h 14m 10.693s = 7.2363035912 h 108° 32' 40.394" = 108.5445538685° Greenwich True Sidereal Time 07h 14m 10.773s = 7.2363258881 h 108° 32' 41.598" = 108.5448883218° ================================================================= Applied Auxiliary Computations Time Factors Corresponding to Full Astronomical JD T = 0.254294113620 Julian centuries reckoned from J2000.0 t = 0.025429411362 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) +1.312" = +0.0003645314° = Nutation in ecliptical longitude +8.629" = +0.0023969810° = Nutation in ecliptical obliquity +0.080s = +0.0003344533° = Equation of the equinoxes Mean Ecliptic Obliquity 23° 26' 09.545" = 23.4359846371° Nutation in Obliquity +8.629" = +0.0023969810° True Ecliptic Obliquity 23° 26' 18.174" = 23.4383816181°
Jay Tanner - PHP Science Labs - 2025 - 1.7