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
2461324.5
0.885219907407
-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 = +76 sec = +00h 01m 16s
Double-Click Within Text Area to Select ALL Text
SIDEREAL TIME FOR GIVEN DATE, TIME AND LONGITUDE Local Date = 2026 Oct 11 [Sunday] Gregorian JD Number = 2461325 JD00 = 2461324.5 = JD for 00h of date Local Time = 21:14:43 = 0.885219907407 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) = 2461325.59355324074 Longitude = -76° 49' 23.915" = -76.8233097222° (W) = -05h 07m 17.594s = -5.1215539815 h ================================================================= Local Mean Sidereal Time at Longitude -76.8233097222° (W) 22h 30m 07.867s = 22.5021853126 h 337° 31' 58.01" = 337.5327796885° Local True Sidereal Time at Longitude = -76.8233097222° (W) 22h 30m 08.357s = 22.5023213112 h 337° 32' 05.35" = 337.5348196680° Greenwich Mean Sidereal Time 03h 37m 25.461s = 3.6237392941 h 54° 21' 21.922" = 54.3560894108° Greenwich True Sidereal Time 03h 37m 25.951s = 3.6238752927 h 54° 21' 29.266" = 54.3581293904° ================================================================= Applied Auxiliary Computations Time Factors Corresponding to Full Astronomical JD T = 0.267778057583 Julian centuries reckoned from J2000.0 t = 0.026777805758 Julian millennia reckoned from J2000.0 Nutations (IAU 2000B Series) +8.004" = +0.0022234340° = Nutation in ecliptical longitude +8.174" = +0.0022706801° = Nutation in ecliptical obliquity +0.490s = +0.0020399795° = Equation of the equinoxes Mean Obliquity of the Ecliptic 23° 26' 08.914" = 23.4358093122° True Obliquity of the Ecliptic 23° 26' 17.088" = 23.4380799923°
Jay Tanner - PHP Science Labs - 2026 - 1.7