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
2460768.5
0.145393518519
-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 Apr 03 [Thursday] Gregorian JD Number = 2460769 JD00 = 2460768.5 = JD for 00h of date Local Time = 03:29:22 = 0.145393518519 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) = 2460768.853726851852 Longitude = -76° 49' 23.915" = -76.8233097222° (W) = -05h 07m 17.594s = -5.1215539815 h ================================================================= Local Mean Sidereal Time at Longitude -76.8233097222° (W) 16h 09m 47.072s = 16.1630755292 h 242° 26' 46.08" = 242.4461329379° Local True Sidereal Time at Longitude = -76.8233097222° (W) 16h 09m 47.105s = 16.1630847757 h 242° 26' 46.58" = 242.4462716354° Greenwich Mean Sidereal Time 21h 17m 04.666s = 21.2846295107 h 319° 16' 09.994" = 319.2694426603° Greenwich True Sidereal Time 21h 17m 04.700s = 21.2846387572 h 319° 16' 10.493" = 319.2695813578° ================================================================= Applied Auxiliary Computations Time Factors Corresponding to Full Astronomical JD T = 0.252535351864 Julian centuries reckoned from J2000.0 t = 0.025253535186 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) +0.544" = +0.0001511711° = Nutation in ecliptical longitude +9.485" = +0.0026347748° = Nutation in ecliptical obliquity +0.033s = +0.0001386975° = Equation of the equinoxes Mean Ecliptic Obliquity 23° 26' 09.627" = 23.4360075054° Nutation in Obliquity +9.485" = +0.0026347748° True Ecliptic Obliquity 23° 26' 19.112" = 23.4386422801°
Jay Tanner - PHP Science Labs - 2025 - 1.7