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
2461355.5
0.139583333333
-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 Nov 11 [Wednesday] Gregorian JD Number = 2461356 JD00 = 2461355.5 = JD for 00h of date Local Time = 03:21:00 = 0.139583333333 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) = 2461355.847916666666 Longitude = -76° 49' 23.915" = -76.8233097222° (W) = -05h 07m 17.594s = -5.1215539815 h ================================================================= Local Mean Sidereal Time at Longitude -76.8233097222° (W) 06h 35m 41.699s = 6.5949164569 h 98° 55' 25.49" = 98.9237468531° Local True Sidereal Time at Longitude = -76.8233097222° (W) 06h 35m 42.189s = 6.5950523939 h 98° 55' 32.83" = 98.9257859078° Greenwich Mean Sidereal Time 11h 42m 59.294s = 11.7164704384 h 175° 44' 49.404" = 175.7470565755° Greenwich True Sidereal Time 11h 42m 59.783s = 11.7166063753 h 175° 44' 56.744" = 175.7490956301° ================================================================= Applied Auxiliary Computations Time Factors Corresponding to Full Astronomical JD T = 0.268606376910 Julian centuries reckoned from J2000.0 t = 0.026860637691 Julian millennia reckoned from J2000.0 Circular Trig Functions of Given Longitude Longitude = -76.8233097222° (W) sin(Lon) = -0.973671722605411 cos(Lon) = +0.227954768756023 tan(Lon) = -4.271337370649689 Nutations (IAU 2000B Series) +8.001" = +0.0022224221° = Nutation in ecliptical longitude +7.391" = +0.0020530348° = Nutation in ecliptical obliquity +0.489s = +0.0020390546° = Equation of the equinoxes Mean Ecliptic Obliquity 23° 26' 08.875" = 23.4357985420° Nutation in Obliquity +7.391" = +0.0020530348° True Ecliptic Obliquity 23° 26' 16.266" = 23.4378515768°
Jay Tanner - PHP Science Labs - 2026 - 1.7