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
2460838.5
0.998032407407
-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 12 [Thursday] Gregorian JD Number = 2460839 JD00 = 2460838.5 = JD for 00h of date Local Time = 23:57:10 = 0.998032407407 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) = 2460839.70636574074 Longitude = -76° 49' 23.915" = -76.8233097222° (W) = -05h 07m 17.594s = -5.1215539815 h ================================================================= Local Mean Sidereal Time at Longitude -76.8233097222° (W) 17h 16m 55.644s = 17.2821233542 h 259° 13' 54.66" = 259.2318503130° Local True Sidereal Time at Longitude = -76.8233097222° (W) 17h 16m 55.759s = 17.2821552521 h 259° 13' 56.38" = 259.2323287816° Greenwich Mean Sidereal Time 22h 24m 13.238s = 22.4036773357 h 336° 03' 18.576" = 336.0551600354° Greenwich True Sidereal Time 22h 24m 13.353s = 22.4037092336 h 336° 03' 20.299" = 336.0556385039° ================================================================= Applied Auxiliary Computations Time Factors Corresponding to Full Astronomical JD T = 0.254475191396 Julian centuries reckoned from J2000.0 t = 0.025447519139 Julian millennia reckoned from J2000.0 Nutations (IAU 2000B Series) +1.877" = +0.0005214980° = Nutation in ecliptical longitude +8.407" = +0.0023353165° = Nutation in ecliptical obliquity +0.115s = +0.0004784685° = Equation of the equinoxes Mean Obliquity of the Ecliptic 23° 26' 09.536" = 23.4359822826° True Obliquity of the Ecliptic 23° 26' 17.943" = 23.4383175991°
Jay Tanner - PHP Science Labs - 2025 - 1.7