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
2460867.5
0.390405092593
-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 11 [Friday] Gregorian JD Number = 2460868 JD00 = 2460867.5 = JD for 00h of date Local Time = 09:22:11 = 0.390405092593 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) = 2460868.098738425926 Longitude = -76° 49' 23.915" = -76.8233097222° (W) = -05h 07m 17.594s = -5.1215539815 h ================================================================= Local Mean Sidereal Time at Longitude -76.8233097222° (W) 04h 33m 53.012s = 4.5647256289 h 68° 28' 15.18" = 68.4708844335° Local True Sidereal Time at Longitude = -76.8233097222° (W) 04h 33m 53.225s = 4.5647848605 h 68° 28' 18.38" = 68.4717729076° Greenwich Mean Sidereal Time 09h 41m 10.607s = 9.6862796104 h 145° 17' 39.099" = 145.2941941558° Greenwich True Sidereal Time 09h 41m 10.820s = 9.6863388420 h 145° 17' 42.297" = 145.2950826300° ================================================================= Applied Auxiliary Computations Time Factors Corresponding to Full Astronomical JD T = 0.255252532195 Julian centuries reckoned from J2000.0 t = 0.025525253219 Julian millennia reckoned from J2000.0 Nutations (IAU 2000B Series) +3.486" = +0.0009683761° = Nutation in ecliptical longitude +8.519" = +0.0023664359° = Nutation in ecliptical obliquity +0.213s = +0.0008884741° = Equation of the equinoxes Mean Obliquity of the Ecliptic 23° 26' 09.500" = 23.4359721752° True Obliquity of the Ecliptic 23° 26' 18.019" = 23.4383386112°
Jay Tanner - PHP Science Labs - 2025 - 1.7