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
2461174.5
0.296643518519
-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 = 2026 May 14 [Thursday] Gregorian JD Number = 2461175 JD00 = 2461174.5 = JD for 00h of date Local Time = 07:07:10 = 0.296643518519 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) = 2461175.004976851852 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 28m 52.331s = 22.4812030056 h 337° 13' 04.96" = 337.2180450838° Local True Sidereal Time at Longitude = -76.8233097222° (W) 22h 28m 52.678s = 22.4812995634 h 337° 13' 10.18" = 337.2194934503° Greenwich Mean Sidereal Time 03h 36m 09.925s = 3.6027569871 h 54° 02' 28.877" = 54.0413548062° Greenwich True Sidereal Time 03h 36m 10.273s = 3.6028535448 h 54° 02' 34.091" = 54.0428031727° ================================================================= Applied Auxiliary Computations Time Factors Corresponding to Full Astronomical JD T = 0.263655167059 Julian centuries reckoned from J2000.0 t = 0.026365516705 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) +5.683" = +0.0015786183° = Nutation in ecliptical longitude +8.213" = +0.0022813512° = Nutation in ecliptical obliquity +0.348s = +0.0014483665° = Equation of the equinoxes Mean Ecliptic Obliquity 23° 26' 09.107" = 23.4358629200° Nutation in Obliquity +8.213" = +0.0022813512° True Ecliptic Obliquity 23° 26' 17.319" = 23.4381442712°
Jay Tanner - PHP Science Labs - 2026 - 1.7