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
2460756.5
0.670752314815
-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 Mar 22 [Saturday] Gregorian JD Number = 2460757 JD00 = 2460756.5 = JD for 00h of date Local Time = 16:05:53 = 0.670752314815 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) = 2460757.379085648148 Longitude = -76° 49' 23.915" = -76.8233097222° (W) = -05h 07m 17.594s = -5.1215539815 h ================================================================= Local Mean Sidereal Time at Longitude -76.8233097222° (W) 04h 01m 03.684s = 4.0176899844 h 60° 15' 55.26" = 60.2653497662° Local True Sidereal Time at Longitude = -76.8233097222° (W) 04h 01m 03.735s = 4.0177042621 h 60° 15' 56.03" = 60.2655639319° Greenwich Mean Sidereal Time 09h 08m 21.278s = 9.1392439659 h 137° 05' 19.174" = 137.0886594886° Greenwich True Sidereal Time 09h 08m 21.330s = 9.1392582436 h 137° 05' 19.945" = 137.0888736543° ================================================================= Applied Auxiliary Computations Time Factors Corresponding to Full Astronomical JD T = 0.252221193310 Julian centuries reckoned from J2000.0 t = 0.025222119331 Julian millennia reckoned from J2000.0 Nutations (IAU 2000B Series) +0.840" = +0.0002334265° = Nutation in ecliptical longitude +9.564" = +0.0026566770° = Nutation in ecliptical obliquity +0.051s = +0.0002141657° = Equation of the equinoxes Mean Obliquity of the Ecliptic 23° 26' 09.642" = 23.4360115902° True Obliquity of the Ecliptic 23° 26' 19.206" = 23.4386682672°
Jay Tanner - PHP Science Labs - 2025 - 1.7