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
2461054.5
0.662210648148
-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 Jan 14 [Wednesday] Gregorian JD Number = 2461055 JD00 = 2461054.5 = JD for 00h of date Local Time = 15:53:35 = 0.662210648148 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) = 2461055.370543981481 Longitude = -76° 49' 23.915" = -76.8233097222° (W) = -05h 07m 17.594s = -5.1215539815 h ================================================================= Local Mean Sidereal Time at Longitude -76.8233097222° (W) 23h 23m 37.163s = 23.3936564925 h 350° 54' 17.45" = 350.9048473868° Local True Sidereal Time at Longitude = -76.8233097222° (W) 23h 23m 37.547s = 23.3937629668 h 350° 54' 23.20" = 350.9064445026° Greenwich Mean Sidereal Time 04h 30m 54.758s = 4.5152104739 h 67° 43' 41.366" = 67.7281571091° Greenwich True Sidereal Time 04h 30m 55.141s = 4.5153169483 h 67° 43' 47.115" = 67.7297542249° ================================================================= Applied Auxiliary Computations Time Factors Corresponding to Full Astronomical JD T = 0.260379754797 Julian centuries reckoned from J2000.0 t = 0.026037975479 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) +6.267" = +0.0017407451° = Nutation in ecliptical longitude +8.198" = +0.0022771748° = Nutation in ecliptical obliquity +0.383s = +0.0015971158° = Equation of the equinoxes Mean Ecliptic Obliquity 23° 26' 09.260" = 23.4359055085° Nutation in Obliquity +8.198" = +0.0022771748° True Ecliptic Obliquity 23° 26' 17.458" = 23.4381826833°
Jay Tanner - PHP Science Labs - 2026 - 1.7