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
2460804.5
0.613981481481
-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 May 09 [Friday] Gregorian JD Number = 2460805 JD00 = 2460804.5 = JD for 00h of date Local Time = 14:44:08 = 0.613981481481 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) = 2460805.322314814814 Longitude = -76° 49' 23.915" = -76.8233097222° (W) = -05h 07m 17.594s = -5.1215539815 h ================================================================= Local Mean Sidereal Time at Longitude -76.8233097222° (W) 05h 48m 19.912s = 5.8055311640 h 87° 04' 58.68" = 87.0829674597° Local True Sidereal Time at Longitude = -76.8233097222° (W) 05h 48m 19.930s = 5.8055361958 h 87° 04' 58.95" = 87.0830429374° Greenwich Mean Sidereal Time 10h 55m 37.507s = 10.9270851455 h 163° 54' 22.598" = 163.9062771820° Greenwich True Sidereal Time 10h 55m 37.525s = 10.9270901773 h 163° 54' 22.870" = 163.9063526598° ================================================================= Applied Auxiliary Computations Time Factors Corresponding to Full Astronomical JD T = 0.253533807387 Julian centuries reckoned from J2000.0 t = 0.025353380738 Julian millennia reckoned from J2000.0 Nutations (IAU 2000B Series) +0.296" = +0.0000822657° = Nutation in ecliptical longitude +9.081" = +0.0025224753° = Nutation in ecliptical obliquity +0.018s = +0.0000754777° = Equation of the equinoxes Mean Obliquity of the Ecliptic 23° 26' 09.580" = 23.4359945229° True Obliquity of the Ecliptic 23° 26' 18.661" = 23.4385169982°
Jay Tanner - PHP Science Labs - 2025 - 1.7