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
2460830.5
0.167581018519
-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 04 [Wednesday] Gregorian JD Number = 2460831 JD00 = 2460830.5 = JD for 00h of date Local Time = 04:01:19 = 0.167581018519 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) = 2460830.875914351852 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 46m 15.753s = 20.7710426085 h 311° 33' 56.30" = 311.5656391271° Local True Sidereal Time at Longitude = -76.8233097222° (W) 20h 46m 15.842s = 20.7710671244 h 311° 33' 57.62" = 311.5660068662° Greenwich Mean Sidereal Time 01h 53m 33.348s = 1.8925965900 h 28° 23' 20.216" = 28.3889488494° Greenwich True Sidereal Time 01h 53m 33.436s = 1.8926211059 h 28° 23' 21.540" = 28.3893165886° ================================================================= Applied Auxiliary Computations Time Factors Corresponding to Full Astronomical JD T = 0.254233426813 Julian centuries reckoned from J2000.0 t = 0.025423342681 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) +1.443" = +0.0004008107° = Nutation in ecliptical longitude +8.690" = +0.0024139498° = Nutation in ecliptical obliquity +0.088s = +0.0003677391° = Equation of the equinoxes Mean Ecliptic Obliquity 23° 26' 09.548" = 23.4359854261° Nutation in Obliquity +8.690" = +0.0024139498° True Ecliptic Obliquity 23° 26' 18.238" = 23.4383993760°
Jay Tanner - PHP Science Labs - 2025 - 1.7