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
2460974.5
0.458715277778
-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 Oct 26 [Sunday] Gregorian JD Number = 2460975 JD00 = 2460974.5 = JD for 00h of date Local Time = 11:00:33 = 0.458715277778 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) = 2460975.167048611111 Longitude = -76° 49' 23.915" = -76.8233097222° (W) = -05h 07m 17.594s = -5.1215539815 h ================================================================= Local Mean Sidereal Time at Longitude -76.8233097222° (W) 13h 14m 22.596s = 13.2396099790 h 198° 35' 38.94" = 198.5941496855° Local True Sidereal Time at Longitude = -76.8233097222° (W) 13h 14m 22.764s = 13.2396566451 h 198° 35' 41.46" = 198.5948496759° Greenwich Mean Sidereal Time 18h 21m 40.190s = 18.3611639605 h 275° 25' 02.854" = 275.4174594078° Greenwich True Sidereal Time 18h 21m 40.358s = 18.3612106265 h 275° 25' 05.374" = 275.4181593982° ================================================================= Applied Auxiliary Computations Time Factors Corresponding to Full Astronomical JD T = 0.258183902768 Julian centuries reckoned from J2000.0 t = 0.025818390276 Julian millennia reckoned from J2000.0 Nutations (IAU 2000B Series) +2.747" = +0.0007629422° = Nutation in ecliptical longitude +8.957" = +0.0024879285° = Nutation in ecliptical obliquity +0.168s = +0.0006999904° = Equation of the equinoxes Mean Obliquity of the Ecliptic 23° 26' 09.363" = 23.4359340601° True Obliquity of the Ecliptic 23° 26' 18.319" = 23.4384219886°
Jay Tanner - PHP Science Labs - 2025 - 1.7