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
2460994.5
0.138263888889
-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 Nov 15 [Saturday] Gregorian JD Number = 2460995 JD00 = 2460994.5 = JD for 00h of date Local Time = 03:19:06 = 0.138263888889 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) = 2460994.846597222222 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 50m 30.899s = 6.8419163325 h 102° 37' 43.48" = 102.6287449873° Local True Sidereal Time at Longitude = -76.8233097222° (W) 06h 50m 31.092s = 6.8419700556 h 102° 37' 46.38" = 102.6295508339° Greenwich Mean Sidereal Time 11h 57m 48.493s = 11.9634703140 h 179° 27' 07.397" = 179.4520547097° Greenwich True Sidereal Time 11h 57m 48.687s = 11.9635240371 h 179° 27' 10.298" = 179.4528605563° ================================================================= Applied Auxiliary Computations Time Factors Corresponding to Full Astronomical JD T = 0.258722699444 Julian centuries reckoned from J2000.0 t = 0.025872269944 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) +3.162" = +0.0008783179° = Nutation in ecliptical longitude +8.753" = +0.0024312729° = Nutation in ecliptical obliquity +0.193s = +0.0008058466° = Equation of the equinoxes Mean Ecliptic Obliquity 23° 26' 09.337" = 23.4359270544° Nutation in Obliquity +8.753" = +0.0024312729° True Ecliptic Obliquity 23° 26' 18.090" = 23.4383583273°
Jay Tanner - PHP Science Labs - 2025 - 1.7