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
2460707.5
0.082442129630
-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 Feb 01 [Saturday] Gregorian JD Number = 2460708 JD00 = 2460707.5 = JD for 00h of date Local Time = 01:58:43 = 0.082442129630 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) = 2460707.790775462963 Longitude = -76° 49' 23.915" = -76.8233097222° (W) = -05h 07m 17.594s = -5.1215539815 h ================================================================= Local Mean Sidereal Time at Longitude -76.8233097222° (W) 10h 38m 23.303s = 10.6398063627 h 159° 35' 49.54" = 159.5970954406° Local True Sidereal Time at Longitude = -76.8233097222° (W) 10h 38m 23.397s = 10.6398323629 h 159° 35' 50.95" = 159.5974854439° Greenwich Mean Sidereal Time 15h 45m 40.897s = 15.7613603442 h 236° 25' 13.459" = 236.4204051630° Greenwich True Sidereal Time 15h 45m 40.991s = 15.7613863444 h 236° 25' 14.863" = 236.4207951662° ================================================================= Applied Auxiliary Computations Time Factors Corresponding to Full Astronomical JD T = 0.250863539369 Julian centuries reckoned from J2000.0 t = 0.025086353936 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) +1.530" = +0.0004250777° = Nutation in ecliptical longitude +9.191" = +0.0025529503° = Nutation in ecliptical obliquity +0.094s = +0.0003900032° = Equation of the equinoxes Mean Ecliptic Obliquity 23° 26' 09.705" = 23.4360292431° Nutation in Obliquity +9.191" = +0.0025529503° True Ecliptic Obliquity 23° 26' 18.896" = 23.4385821934°
Jay Tanner - PHP Science Labs - 2025 - 1.7