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
2461064.5
0.619027777778
-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 Jan 24 [Saturday] Gregorian JD Number = 2461065 JD00 = 2461064.5 = JD for 00h of date Local Time = 14:51:24 = 0.619027777778 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) = 2461065.327361111111 Longitude = -76° 49' 23.915" = -76.8233097222° (W) = -05h 07m 17.594s = -5.1215539815 h ================================================================= Local Mean Sidereal Time at Longitude -76.8233097222° (W) 23h 00m 41.502s = 23.0115283125 h 345° 10' 22.53" = 345.1729246881° Local True Sidereal Time at Longitude = -76.8233097222° (W) 23h 00m 41.905s = 23.0116402236 h 345° 10' 28.57" = 345.1746033540° Greenwich Mean Sidereal Time 04h 07m 59.096s = 4.1330822940 h 61° 59' 46.444" = 61.9962344104° Greenwich True Sidereal Time 04h 07m 59.499s = 4.1331942051 h 61° 59' 52.487" = 61.9979130763° ================================================================= Applied Auxiliary Computations Time Factors Corresponding to Full Astronomical JD T = 0.260652357593 Julian centuries reckoned from J2000.0 t = 0.026065235759 Julian millennia reckoned from J2000.0 Nutations (IAU 2000B Series) +6.587" = +0.0018296303° = Nutation in ecliptical longitude +8.530" = +0.0023693501° = Nutation in ecliptical obliquity +0.403s = +0.0016786659° = Equation of the equinoxes Mean Obliquity of the Ecliptic 23° 26' 09.247" = 23.4359019640° True Obliquity of the Ecliptic 23° 26' 17.777" = 23.4382713141°
Jay Tanner - PHP Science Labs - 2026 - 1.7