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
2460713.5
0.963379629630
-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 = 2025 Feb 07 [Friday] Gregorian JD Number = 2460714 JD00 = 2460713.5 = JD for 00h of date Local Time = 23:07:16 = 0.963379629630 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) = 2460714.671712962963 Longitude = -76° 49' 23.915" = -76.8233097222° (W) = -05h 07m 17.594s = -5.1215539815 h ================================================================= Local Mean Sidereal Time at Longitude -76.8233097222° (W) 08h 14m 04.026s = 8.2344515583 h 123° 31' 00.38" = 123.5167733752° Local True Sidereal Time at Longitude = -76.8233097222° (W) 08h 14m 04.122s = 8.2344783693 h 123° 31' 01.83" = 123.5171755394° Greenwich Mean Sidereal Time 13h 21m 21.620s = 13.3560055398 h 200° 20' 24.299" = 200.3400830976° Greenwich True Sidereal Time 13h 21m 21.716s = 13.3560323508 h 200° 20' 25.747" = 200.3404852617° ================================================================= Applied Auxiliary Computations Time Factors Corresponding to Full Astronomical JD T = 0.251051929170 Julian centuries reckoned from J2000.0 t = 0.025105192917 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) +1.578" = +0.0004383322° = Nutation in ecliptical longitude +9.092" = +0.0025254573° = Nutation in ecliptical obliquity +0.097s = +0.0004021642° = Equation of the equinoxes Mean Ecliptic Obliquity 23° 26' 09.696" = 23.4360267936° Nutation in Obliquity +9.092" = +0.0025254573° True Ecliptic Obliquity 23° 26' 18.788" = 23.4385522508°
Jay Tanner - PHP Science Labs - 2025 - 1.7