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
2460698.5
0.057094907407
-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 = +74 sec = +00h 01m 14s
Double-Click Within Text Area to Select ALL Text
SIDEREAL TIME FOR GIVEN DATE, TIME AND LONGITUDE Local Date = 2025 Jan 23 [Thursday] Gregorian JD Number = 2460699 JD00 = 2460698.5 = JD for 00h of date Local Time = 01:22:13 = 0.057094907407 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) = 2460698.76542824074 Longitude = -76° 49' 23.915" = -76.8233097222° (W) = -05h 07m 17.594s = -5.1215539815 h ================================================================= Local Mean Sidereal Time at Longitude -76.8233097222° (W) 09h 26m 18.309s = 9.4384190476 h 141° 34' 34.63" = 141.5762857143° Local True Sidereal Time at Longitude = -76.8233097222° (W) 09h 26m 18.364s = 9.4384344553 h 141° 34' 35.46" = 141.5765168300° Greenwich Mean Sidereal Time 14h 33m 35.903s = 14.5599730291 h 218° 23' 58.544" = 218.3995954366° Greenwich True Sidereal Time 14h 33m 35.958s = 14.5599884368 h 218° 23' 59.376" = 218.3998265524° ================================================================= Applied Auxiliary Computations Time Factors Corresponding to Full Astronomical JD T = 0.250616438829 Julian centuries reckoned from J2000.0 t = 0.025061643882 Julian millennia reckoned from J2000.0 Nutations (IAU 2000B Series) +0.907" = +0.0002519007° = Nutation in ecliptical longitude +8.879" = +0.0024662999° = Nutation in ecliptical obliquity +0.055s = +0.0002311157° = Equation of the equinoxes Mean Obliquity of the Ecliptic 23° 26' 09.717" = 23.4360324560° True Obliquity of the Ecliptic 23° 26' 18.596" = 23.4384987560°
Jay Tanner - PHP Science Labs - 2025 - 1.7