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
2460967.5
0.125416666667
-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 Oct 19 [Sunday] Gregorian JD Number = 2460968 JD00 = 2460967.5 = JD for 00h of date Local Time = 03:00:36 = 0.125416666667 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) = 2460967.83375 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 45m 30.865s = 4.7585735484 h 71° 22' 42.97" = 71.3786032265° Local True Sidereal Time at Longitude = -76.8233097222° (W) 04h 45m 31.042s = 4.7586227439 h 71° 22' 45.63" = 71.3793411583° Greenwich Mean Sidereal Time 09h 52m 48.459s = 9.8801275299 h 148° 12' 06.887" = 148.2019129489° Greenwich True Sidereal Time 09h 52m 48.636s = 9.8801767254 h 148° 12' 09.543" = 148.2026508807° ================================================================= Applied Auxiliary Computations Time Factors Corresponding to Full Astronomical JD T = 0.257983127994 Julian centuries reckoned from J2000.0 t = 0.025798312799 Julian millennia reckoned from J2000.0 Nutations (IAU 2000B Series) +2.895" = +0.0008042964° = Nutation in ecliptical longitude +9.315" = +0.0025875946° = Nutation in ecliptical obliquity +0.177s = +0.0007379318° = Equation of the equinoxes Mean Obliquity of the Ecliptic 23° 26' 09.372" = 23.4359366707° True Obliquity of the Ecliptic 23° 26' 18.687" = 23.4385242653°
Jay Tanner - PHP Science Labs - 2025 - 1.7