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
2460860.5
0.517430555556
-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 Jul 04 [Friday] Gregorian JD Number = 2460861 JD00 = 2460860.5 = JD for 00h of date Local Time = 12:25:06 = 0.517430555556 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) = 2460861.225763888889 Longitude = -76° 49' 23.915" = -76.8233097222° (W) = -05h 07m 17.594s = -5.1215539815 h ================================================================= Local Mean Sidereal Time at Longitude -76.8233097222° (W) 07h 09m 42.173s = 7.1617147920 h 107° 25' 32.60" = 107.4257218801° Local True Sidereal Time at Longitude = -76.8233097222° (W) 07h 09m 42.343s = 7.1617620406 h 107° 25' 35.15" = 107.4264306086° Greenwich Mean Sidereal Time 12h 16m 59.768s = 12.2832687735 h 184° 14' 56.514" = 184.2490316024° Greenwich True Sidereal Time 12h 16m 59.938s = 12.2833160221 h 184° 14' 59.065" = 184.2497403310° ================================================================= Applied Auxiliary Computations Time Factors Corresponding to Full Astronomical JD T = 0.255064360407 Julian centuries reckoned from J2000.0 t = 0.025506436040 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) +2.781" = +0.0007724658° = Nutation in ecliptical longitude +8.557" = +0.0023768802° = Nutation in ecliptical obliquity +0.170s = +0.0007087286° = Equation of the equinoxes Mean Ecliptic Obliquity 23° 26' 09.509" = 23.4359746219° Nutation in Obliquity +8.557" = +0.0023768802° True Ecliptic Obliquity 23° 26' 18.065" = 23.4383515021°
Jay Tanner - PHP Science Labs - 2025 - 1.7