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
2461115.5
0.181643518519
-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 Mar 16 [Monday] Gregorian JD Number = 2461116 JD00 = 2461115.5 = JD for 00h of date Local Time = 04:21:34 = 0.181643518519 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) = 2461115.889976851852 Longitude = -76° 49' 23.915" = -76.8233097222° (W) = -05h 07m 17.594s = -5.1215539815 h ================================================================= Local Mean Sidereal Time at Longitude -76.8233097222° (W) 15h 50m 12.360s = 15.8367667076 h 237° 33' 05.40" = 237.5515006147° Local True Sidereal Time at Longitude = -76.8233097222° (W) 15h 50m 12.774s = 15.8368816818 h 237° 33' 11.61" = 237.5532252271° Greenwich Mean Sidereal Time 20h 57m 29.954s = 20.9583206891 h 314° 22' 29.317" = 314.3748103371° Greenwich True Sidereal Time 20h 57m 30.368s = 20.9584356633 h 314° 22' 35.526" = 314.3765349495° ================================================================= Applied Auxiliary Computations Time Factors Corresponding to Full Astronomical JD T = 0.262036686566 Julian centuries reckoned from J2000.0 t = 0.026203668656 Julian millennia reckoned from J2000.0 Nutations (IAU 2000B Series) +6.767" = +0.0018797108° = Nutation in ecliptical longitude +9.096" = +0.0025266580° = Nutation in ecliptical obliquity +0.414s = +0.0017246124° = Equation of the equinoxes Mean Obliquity of the Ecliptic 23° 26' 09.182" = 23.4358839643° True Obliquity of the Ecliptic 23° 26' 18.278" = 23.4384106223°
Jay Tanner - PHP Science Labs - 2026 - 1.7