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
2461082.5
0.131562500000
-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 11 [Wednesday] Gregorian JD Number = 2461083 JD00 = 2461082.5 = JD for 00h of date Local Time = 03:09:27 = 0.131562500000 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) = 2461082.839895833333 Longitude = -76° 49' 23.915" = -76.8233097222° (W) = -05h 07m 17.594s = -5.1215539815 h ================================================================= Local Mean Sidereal Time at Longitude -76.8233097222° (W) 12h 27m 47.186s = 12.4631072340 h 186° 56' 47.79" = 186.9466085103° Local True Sidereal Time at Longitude = -76.8233097222° (W) 12h 27m 47.615s = 12.4632263984 h 186° 56' 54.23" = 186.9483959762° Greenwich Mean Sidereal Time 17h 35m 04.780s = 17.5846612155 h 263° 46' 11.706" = 263.7699182327° Greenwich True Sidereal Time 17h 35m 05.209s = 17.5847803799 h 263° 46' 18.141" = 263.7717056985° ================================================================= Applied Auxiliary Computations Time Factors Corresponding to Full Astronomical JD T = 0.261131824663 Julian centuries reckoned from J2000.0 t = 0.026113182466 Julian millennia reckoned from J2000.0 Nutations (IAU 2000B Series) +7.014" = +0.0019482151° = Nutation in ecliptical longitude +8.643" = +0.0024008160° = Nutation in ecliptical obliquity +0.429s = +0.0017874658° = Equation of the equinoxes Mean Obliquity of the Ecliptic 23° 26' 09.225" = 23.4358957298° True Obliquity of the Ecliptic 23° 26' 17.868" = 23.4382965457°
Jay Tanner - PHP Science Labs - 2026 - 1.7