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
2461069.5
0.900266203704
-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 = 2026 Jan 29 [Thursday] Gregorian JD Number = 2461070 JD00 = 2461069.5 = JD for 00h of date Local Time = 21:36:23 = 0.900266203704 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) = 2461070.608599537037 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 06m 29.807s = 6.1082797879 h 91° 37' 27.11" = 91.6241968186° Local True Sidereal Time at Longitude = -76.8233097222° (W) 06h 06m 30.237s = 6.1083990644 h 91° 37' 33.55" = 91.6259859654° Greenwich Mean Sidereal Time 11h 13m 47.402s = 11.2298337694 h 168° 26' 51.024" = 168.4475065409° Greenwich True Sidereal Time 11h 13m 47.831s = 11.2299530459 h 168° 26' 57.464" = 168.4492956878° ================================================================= Applied Auxiliary Computations Time Factors Corresponding to Full Astronomical JD T = 0.260796950021 Julian centuries reckoned from J2000.0 t = 0.026079695002 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) +7.020" = +0.0019500463° = Nutation in ecliptical longitude +8.397" = +0.0023325649° = Nutation in ecliptical obliquity +0.429s = +0.0017891468° = Equation of the equinoxes Mean Ecliptic Obliquity 23° 26' 09.240" = 23.4359000840° Nutation in Obliquity +8.397" = +0.0023325649° True Ecliptic Obliquity 23° 26' 17.638" = 23.4382326489°
Jay Tanner - PHP Science Labs - 2026 - 1.7