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
2461017.5
0.184340277778
-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 08 [Monday] Gregorian JD Number = 2461018 JD00 = 2461017.5 = JD for 00h of date Local Time = 04:25:27 = 0.184340277778 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) = 2461017.892673611111 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 27m 43.572s = 9.4621033107 h 141° 55' 53.58" = 141.9315496609° Local True Sidereal Time at Longitude = -76.8233097222° (W) 09h 27m 43.846s = 9.4621795726 h 141° 55' 57.70" = 141.9326935886° Greenwich Mean Sidereal Time 14h 35m 01.166s = 14.5836572922 h 218° 45' 17.494" = 218.7548593832° Greenwich True Sidereal Time 14h 35m 01.441s = 14.5837335541 h 218° 45' 21.612" = 218.7560033110° ================================================================= Applied Auxiliary Computations Time Factors Corresponding to Full Astronomical JD T = 0.259353666628 Julian centuries reckoned from J2000.0 t = 0.025935366662 Julian millennia reckoned from J2000.0 Nutations (IAU 2000B Series) +4.488" = +0.0012468017° = Nutation in ecliptical longitude +8.192" = +0.0022755860° = Nutation in ecliptical obliquity +0.275s = +0.0011439277° = Equation of the equinoxes Mean Obliquity of the Ecliptic 23° 26' 09.308" = 23.4359188502° True Obliquity of the Ecliptic 23° 26' 17.500" = 23.4381944362°
Jay Tanner - PHP Science Labs - 2025 - 1.7