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
2460839.5
0.647951388889
-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 Jun 13 [Friday] Gregorian JD Number = 2460840 JD00 = 2460839.5 = JD for 00h of date Local Time = 15:33:03 = 0.647951388889 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) = 2460840.356284722222 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 55m 22.386s = 8.9228849693 h 133° 50' 35.79" = 133.8432745389° Local True Sidereal Time at Longitude = -76.8233097222° (W) 08h 55m 22.506s = 8.9229183815 h 133° 50' 37.59" = 133.8437757232° Greenwich Mean Sidereal Time 14h 02m 39.980s = 14.0444389507 h 210° 39' 59.703" = 210.6665842612° Greenwich True Sidereal Time 14h 02m 40.101s = 14.0444723630 h 210° 40' 01.508" = 210.6670854456° ================================================================= Applied Auxiliary Computations Time Factors Corresponding to Full Astronomical JD T = 0.254492985208 Julian centuries reckoned from J2000.0 t = 0.025449298520 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) +1.967" = +0.0005462567° = Nutation in ecliptical longitude +8.423" = +0.0023397781° = Nutation in ecliptical obliquity +0.120s = +0.0005011844° = Equation of the equinoxes Mean Ecliptic Obliquity 23° 26' 09.535" = 23.4359820512° Nutation in Obliquity +8.423" = +0.0023397781° True Ecliptic Obliquity 23° 26' 17.959" = 23.4383218293°
Jay Tanner - PHP Science Labs - 2025 - 1.7