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
0.331574074074
-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 = 07:57:28 = 0.331574074074 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) = 2460768.039907407407 Longitude = -76° 49' 23.915" = -76.8233097222° (W) = -05h 07m 17.594s = -5.1215539815 h ================================================================= Local Mean Sidereal Time at Longitude -76.8233097222° (W) 20h 34m 40.559s = 20.5779329336 h 308° 40' 08.38" = 308.6689940039° Local True Sidereal Time at Longitude = -76.8233097222° (W) 20h 34m 40.586s = 20.5779406206 h 308° 40' 08.79" = 308.6691093095° Greenwich Mean Sidereal Time 01h 41m 58.153s = 1.6994869151 h 25° 29' 32.293" = 25.4923037263° Greenwich True Sidereal Time 01h 41m 58.181s = 1.6994946021 h 25° 29' 32.709" = 25.4924190319° ================================================================= Applied Auxiliary Computations Time Factors Corresponding to Full Astronomical JD T = 0.252513070702 Julian centuries reckoned from J2000.0 t = 0.025251307070 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) +0.452" = +0.0001256756° = Nutation in ecliptical longitude +9.516" = +0.0026433261° = Nutation in ecliptical obliquity +0.028s = +0.0001153056° = Equation of the equinoxes Mean Ecliptic Obliquity 23° 26' 09.628" = 23.4360077951° Nutation in Obliquity +9.516" = +0.0026433261° True Ecliptic Obliquity 23° 26' 19.144" = 23.4386511212°
Jay Tanner - PHP Science Labs - 2025 - 1.7