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
2461080.5
0.906111111111
-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 Feb 09 [Monday] Gregorian JD Number = 2461081 JD00 = 2461080.5 = JD for 00h of date Local Time = 21:44:48 = 0.906111111111 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) = 2461081.614444444444 Longitude = -76° 49' 23.915" = -76.8233097222° (W) = -05h 07m 17.594s = -5.1215539815 h ================================================================= Local Mean Sidereal Time at Longitude -76.8233097222° (W) 06h 58m 18.299s = 6.9717497053 h 104° 34' 34.48" = 104.5762455794° Local True Sidereal Time at Longitude = -76.8233097222° (W) 06h 58m 18.724s = 6.9718676522 h 104° 34' 40.85" = 104.5780147837° Greenwich Mean Sidereal Time 12h 05m 35.893s = 12.0933036868 h 181° 23' 58.399" = 181.3995553018° Greenwich True Sidereal Time 12h 05m 36.318s = 12.0934216337 h 181° 24' 04.768" = 181.4013245061° ================================================================= Applied Auxiliary Computations Time Factors Corresponding to Full Astronomical JD T = 0.261098273632 Julian centuries reckoned from J2000.0 t = 0.026109827363 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) +6.942" = +0.0019283114° = Nutation in ecliptical longitude +8.663" = +0.0024062768° = Nutation in ecliptical obliquity +0.425s = +0.0017692043° = Equation of the equinoxes Mean Ecliptic Obliquity 23° 26' 09.226" = 23.4358961660° Nutation in Obliquity +8.663" = +0.0024062768° True Ecliptic Obliquity 23° 26' 17.889" = 23.4383024428°
Jay Tanner - PHP Science Labs - 2026 - 1.7