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
2460857.5
0.719756944444
-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 01 [Tuesday] Gregorian JD Number = 2460858 JD00 = 2460857.5 = JD for 00h of date Local Time = 17:16:27 = 0.719756944444 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) = 2460858.428090277777 Longitude = -76° 49' 23.915" = -76.8233097222° (W) = -05h 07m 17.594s = -5.1215539815 h ================================================================= Local Mean Sidereal Time at Longitude -76.8233097222° (W) 11h 50m 01.369s = 11.8337134747 h 177° 30' 20.53" = 177.5057021212° Local True Sidereal Time at Longitude = -76.8233097222° (W) 11h 50m 01.546s = 11.8337628231 h 177° 30' 23.19" = 177.5064423472° Greenwich Mean Sidereal Time 16h 57m 18.963s = 16.9552674562 h 254° 19' 44.443" = 254.3290118435° Greenwich True Sidereal Time 16h 57m 19.140s = 16.9553168046 h 254° 19' 47.107" = 254.3297520696° ================================================================= Applied Auxiliary Computations Time Factors Corresponding to Full Astronomical JD T = 0.254987764278 Julian centuries reckoned from J2000.0 t = 0.025498776427 Julian millennia reckoned from J2000.0 Nutations (IAU 2000B Series) +2.904" = +0.0008067960° = Nutation in ecliptical longitude +8.612" = +0.0023921834° = Nutation in ecliptical obliquity +0.178s = +0.0007402260° = Equation of the equinoxes Mean Obliquity of the Ecliptic 23° 26' 09.512" = 23.4359756179° True Obliquity of the Ecliptic 23° 26' 18.124" = 23.4383678012°
Jay Tanner - PHP Science Labs - 2025 - 1.7