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
2461161.5
0.787569444444
-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 May 01 [Friday] Gregorian JD Number = 2461162 JD00 = 2461161.5 = JD for 00h of date Local Time = 18:54:06 = 0.787569444444 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) = 2461162.495902777777 Longitude = -76° 49' 23.915" = -76.8233097222° (W) = -05h 07m 17.594s = -5.1215539815 h ================================================================= Local Mean Sidereal Time at Longitude -76.8233097222° (W) 09h 26m 29.242s = 9.4414561586 h 141° 37' 18.63" = 141.6218423797° Local True Sidereal Time at Longitude = -76.8233097222° (W) 09h 26m 29.581s = 9.4415502753 h 141° 37' 23.71" = 141.6232541293° Greenwich Mean Sidereal Time 14h 33m 46.837s = 14.5630101401 h 218° 26' 42.548" = 218.4451521020° Greenwich True Sidereal Time 14h 33m 47.175s = 14.5631042568 h 218° 26' 47.630" = 218.4465638516° ================================================================= Applied Auxiliary Computations Time Factors Corresponding to Full Astronomical JD T = 0.263312687276 Julian centuries reckoned from J2000.0 t = 0.026331268727 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) +5.539" = +0.0015387090° = Nutation in ecliptical longitude +8.403" = +0.0023341878° = Nutation in ecliptical obliquity +0.339s = +0.0014117496° = Equation of the equinoxes Mean Ecliptic Obliquity 23° 26' 09.123" = 23.4358673731° Nutation in Obliquity +8.403" = +0.0023341878° True Ecliptic Obliquity 23° 26' 17.526" = 23.4382015609°
Jay Tanner - PHP Science Labs - 2026 - 1.7