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
2460769.5
0.112303240741
-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 04 [Friday] Gregorian JD Number = 2460770 JD00 = 2460769.5 = JD for 00h of date Local Time = 02:41:43 = 0.112303240741 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) = 2460769.820636574074 Longitude = -76° 49' 23.915" = -76.8233097222° (W) = -05h 07m 17.594s = -5.1215539815 h ================================================================= Local Mean Sidereal Time at Longitude -76.8233097222° (W) 15h 25m 56.800s = 15.4324443358 h 231° 29' 11.99" = 231.4866650375° Local True Sidereal Time at Longitude = -76.8233097222° (W) 15h 25m 56.840s = 15.4324555238 h 231° 29' 12.60" = 231.4868328569° Greenwich Mean Sidereal Time 20h 33m 14.394s = 20.5539983173 h 308° 18' 35.909" = 308.3099747598° Greenwich True Sidereal Time 20h 33m 14.434s = 20.5540095053 h 308° 18' 36.513" = 308.3101425793° ================================================================= Applied Auxiliary Computations Time Factors Corresponding to Full Astronomical JD T = 0.252561824409 Julian centuries reckoned from J2000.0 t = 0.025256182440 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) +0.658" = +0.0001829122° = Nutation in ecliptical longitude +9.473" = +0.0026314620° = Nutation in ecliptical obliquity +0.040s = +0.0001678195° = Equation of the equinoxes Mean Ecliptic Obliquity 23° 26' 09.626" = 23.4360071611° Nutation in Obliquity +9.473" = +0.0026314620° True Ecliptic Obliquity 23° 26' 19.099" = 23.4386386231°
Jay Tanner - PHP Science Labs - 2025 - 1.7