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
2460932.5
0.401087962963
-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 Sep 14 [Sunday] Gregorian JD Number = 2460933 JD00 = 2460932.5 = JD for 00h of date Local Time = 09:37:34 = 0.401087962963 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) = 2460933.109421296296 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 05m 34.638s = 9.0929551045 h 136° 23' 39.58" = 136.3943265672° Local True Sidereal Time at Longitude = -76.8233097222° (W) 09h 05m 34.866s = 9.0930184151 h 136° 23' 42.99" = 136.3952762260° Greenwich Mean Sidereal Time 14h 12m 52.233s = 14.2145090860 h 213° 13' 03.491" = 213.2176362895° Greenwich True Sidereal Time 14h 12m 52.461s = 14.2145723966 h 213° 13' 06.909" = 213.2185859483° ================================================================= Applied Auxiliary Computations Time Factors Corresponding to Full Astronomical JD T = 0.257032427687 Julian centuries reckoned from J2000.0 t = 0.025703242768 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) +3.726" = +0.0010350648° = Nutation in ecliptical longitude +9.337" = +0.0025935972° = Nutation in ecliptical obliquity +0.228s = +0.0009496588° = Equation of the equinoxes Mean Ecliptic Obliquity 23° 26' 09.417" = 23.4359490321° Nutation in Obliquity +9.337" = +0.0025935972° True Ecliptic Obliquity 23° 26' 18.753" = 23.4385426293°
Jay Tanner - PHP Science Labs - 2025 - 1.7