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
2460846.5
0.189791666667
-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 Jun 20 [Friday] Gregorian JD Number = 2460847 JD00 = 2460846.5 = JD for 00h of date Local Time = 04:33:18 = 0.189791666667 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) = 2460846.898125 Longitude = -76° 49' 23.915" = -76.8233097222° (W) = -05h 07m 17.594s = -5.1215539815 h ================================================================= Local Mean Sidereal Time at Longitude -76.8233097222° (W) 22h 21m 24.893s = 22.3569148103 h 335° 21' 13.40" = 335.3537221551° Local True Sidereal Time at Longitude = -76.8233097222° (W) 22h 21m 25.014s = 22.3569483687 h 335° 21' 15.21" = 335.3542255301° Greenwich Mean Sidereal Time 03h 28m 42.488s = 3.4784687918 h 52° 10' 37.315" = 52.1770318775° Greenwich True Sidereal Time 03h 28m 42.608s = 3.4785023502 h 52° 10' 39.127" = 52.1775352525° ================================================================= Applied Auxiliary Computations Time Factors Corresponding to Full Astronomical JD T = 0.254672091033 Julian centuries reckoned from J2000.0 t = 0.025467209103 Julian millennia reckoned from J2000.0 Nutations (IAU 2000B Series) +1.975" = +0.0005486445° = Nutation in ecliptical longitude +8.569" = +0.0023803777° = Nutation in ecliptical obliquity +0.121s = +0.0005033750° = Equation of the equinoxes Mean Obliquity of the Ecliptic 23° 26' 09.527" = 23.4359797224° True Obliquity of the Ecliptic 23° 26' 18.096" = 23.4383601001°
Jay Tanner - PHP Science Labs - 2025 - 1.7