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
2460791.5
0.198750000000
-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 26 [Saturday] Gregorian JD Number = 2460792 JD00 = 2460791.5 = JD for 00h of date Local Time = 04:46:12 = 0.198750000000 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) = 2460791.907083333333 Longitude = -76° 49' 23.915" = -76.8233097222° (W) = -05h 07m 17.594s = -5.1215539815 h ================================================================= Local Mean Sidereal Time at Longitude -76.8233097222° (W) 18h 57m 30.467s = 18.9584631053 h 284° 22' 37.01" = 284.3769465801° Local True Sidereal Time at Longitude = -76.8233097222° (W) 18h 57m 30.471s = 18.9584640814 h 284° 22' 37.06" = 284.3769612216° Greenwich Mean Sidereal Time 00h 04m 48.062s = 0.0800170868 h 01° 12' 00.923" = 1.2002563025° Greenwich True Sidereal Time 00h 04m 48.065s = 0.0800180629 h 01° 12' 00.975" = 1.2002709439° ================================================================= Applied Auxiliary Computations Time Factors Corresponding to Full Astronomical JD T = 0.253166518366 Julian centuries reckoned from J2000.0 t = 0.025316651836 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) +0.057" = +0.0000159582° = Nutation in ecliptical longitude +9.363" = +0.0026007294° = Nutation in ecliptical obliquity +0.004s = +0.0000146414° = Equation of the equinoxes Mean Ecliptic Obliquity 23° 26' 09.597" = 23.4359992986° Nutation in Obliquity +9.363" = +0.0026007294° True Ecliptic Obliquity 23° 26' 18.960" = 23.4386000280°
Jay Tanner - PHP Science Labs - 2025 - 1.7