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
2460858.5
0.166990740741
-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 Jul 02 [Wednesday] Gregorian JD Number = 2460859 JD00 = 2460858.5 = JD for 00h of date Local Time = 04:00:28 = 0.166990740741 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) = 2460858.875324074074 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 35m 48.164s = 22.5967122472 h 338° 57' 02.46" = 338.9506837078° Local True Sidereal Time at Longitude = -76.8233097222° (W) 22h 35m 48.340s = 22.5967610871 h 338° 57' 05.10" = 338.9514163064° Greenwich Mean Sidereal Time 03h 43m 05.758s = 3.7182662287 h 55° 46' 26.376" = 55.7739934302° Greenwich True Sidereal Time 03h 43m 05.934s = 3.7183150686 h 55° 46' 29.014" = 55.7747260288° ================================================================= Applied Auxiliary Computations Time Factors Corresponding to Full Astronomical JD T = 0.255000008872 Julian centuries reckoned from J2000.0 t = 0.025500000887 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) +2.875" = +0.0007984826° = Nutation in ecliptical longitude +8.611" = +0.0023920673° = Nutation in ecliptical obliquity +0.176s = +0.0007325986° = Equation of the equinoxes Mean Ecliptic Obliquity 23° 26' 09.512" = 23.4359754587° Nutation in Obliquity +8.611" = +0.0023920673° True Ecliptic Obliquity 23° 26' 18.123" = 23.4383675260°
Jay Tanner - PHP Science Labs - 2025 - 1.7