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
2461016.5
0.708553240741
-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 Dec 07 [Sunday] Gregorian JD Number = 2461017 JD00 = 2461016.5 = JD for 00h of date Local Time = 17:00:19 = 0.708553240741 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) = 2461017.416886574074 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 00m 43.022s = 22.0119505386 h 330° 10' 45.33" = 330.1792580797° Local True Sidereal Time at Longitude = -76.8233097222° (W) 22h 00m 43.293s = 22.0120257019 h 330° 10' 49.39" = 330.1803855279° Greenwich Mean Sidereal Time 03h 08m 00.616s = 3.1335045201 h 47° 00' 09.244" = 47.0025678021° Greenwich True Sidereal Time 03h 08m 00.887s = 3.1335796834 h 47° 00' 13.303" = 47.0036952503° ================================================================= Applied Auxiliary Computations Time Factors Corresponding to Full Astronomical JD T = 0.259340640289 Julian centuries reckoned from J2000.0 t = 0.025934064028 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) +4.424" = +0.0012288402° = Nutation in ecliptical longitude +8.171" = +0.0022698520° = Nutation in ecliptical obliquity +0.271s = +0.0011274482° = Equation of the equinoxes Mean Ecliptic Obliquity 23° 26' 09.308" = 23.4359190196° Nutation in Obliquity +8.171" = +0.0022698520° True Ecliptic Obliquity 23° 26' 17.480" = 23.4381888716°
Jay Tanner - PHP Science Labs - 2025 - 1.7