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
2460711.5
0.451481481481
-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 05 [Wednesday] Gregorian JD Number = 2460712 JD00 = 2460711.5 = JD for 00h of date Local Time = 10:50:08 = 0.451481481481 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) = 2460712.159814814814 Longitude = -76° 49' 23.915" = -76.8233097222° (W) = -05h 07m 17.594s = -5.1215539815 h ================================================================= Local Mean Sidereal Time at Longitude -76.8233097222° (W) 19h 47m 01.823s = 19.7838396222 h 296° 45' 27.34" = 296.7575943330° Local True Sidereal Time at Longitude = -76.8233097222° (W) 19h 47m 01.902s = 19.7838616565 h 296° 45' 28.53" = 296.7579248470° Greenwich Mean Sidereal Time 00h 54m 19.417s = 0.9053936037 h 13° 34' 51.255" = 13.5809040554° Greenwich True Sidereal Time 00h 54m 19.496s = 0.9054156380 h 13° 34' 52.444" = 13.5812345694° ================================================================= Applied Auxiliary Computations Time Factors Corresponding to Full Astronomical JD T = 0.250983157147 Julian centuries reckoned from J2000.0 t = 0.025098315714 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) +1.297" = +0.0003602383° = Nutation in ecliptical longitude +9.135" = +0.0025374539° = Nutation in ecliptical obliquity +0.079s = +0.0003305140° = Equation of the equinoxes Mean Ecliptic Obliquity 23° 26' 09.700" = 23.4360276878° Nutation in Obliquity +9.135" = +0.0025374539° True Ecliptic Obliquity 23° 26' 18.835" = 23.4385651416°
Jay Tanner - PHP Science Labs - 2025 - 1.7