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
2460767.5
0.369444444444
-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 Apr 02 [Wednesday] Gregorian JD Number = 2460768 JD00 = 2460767.5 = JD for 00h of date Local Time = 08:52:00 = 0.369444444444 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) = 2460768.077777777777 Longitude = -76° 49' 23.915" = -76.8233097222° (W) = -05h 07m 17.594s = -5.1215539815 h ================================================================= Local Mean Sidereal Time at Longitude -76.8233097222° (W) 21h 29m 21.517s = 21.4893102766 h 322° 20' 22.75" = 322.3396541490° Local True Sidereal Time at Longitude = -76.8233097222° (W) 21h 29m 21.545s = 21.4893180297 h 322° 20' 23.17" = 322.3397704451° Greenwich Mean Sidereal Time 02h 36m 39.111s = 2.6108642581 h 39° 09' 46.670" = 39.1629638714° Greenwich True Sidereal Time 02h 36m 39.139s = 2.6108720112 h 39° 09' 47.089" = 39.1630801675° ================================================================= Applied Auxiliary Computations Time Factors Corresponding to Full Astronomical JD T = 0.252514107536 Julian centuries reckoned from J2000.0 t = 0.025251410753 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) +0.456" = +0.0001267551° = Nutation in ecliptical longitude +9.514" = +0.0026428159° = Nutation in ecliptical obliquity +0.028s = +0.0001162961° = Equation of the equinoxes Mean Ecliptic Obliquity 23° 26' 09.628" = 23.4360077816° Nutation in Obliquity +9.514" = +0.0026428159° True Ecliptic Obliquity 23° 26' 19.142" = 23.4386505974°
Jay Tanner - PHP Science Labs - 2025 - 1.7