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
2460859.5
0.076284722222
-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 Jul 03 [Thursday] Gregorian JD Number = 2460860 JD00 = 2460859.5 = JD for 00h of date Local Time = 01:49:51 = 0.076284722222 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) = 2460859.784618055555 Longitude = -76° 49' 23.915" = -76.8233097222° (W) = -05h 07m 17.594s = -5.1215539815 h ================================================================= Local Mean Sidereal Time at Longitude -76.8233097222° (W) 20h 28m 46.262s = 20.4795173458 h 307° 11' 33.94" = 307.1927601877° Local True Sidereal Time at Longitude = -76.8233097222° (W) 20h 28m 46.435s = 20.4795652801 h 307° 11' 36.52" = 307.1934792021° Greenwich Mean Sidereal Time 01h 36m 03.857s = 1.6010713273 h 24° 00' 57.852" = 24.0160699100° Greenwich True Sidereal Time 01h 36m 04.029s = 1.6011192616 h 24° 01' 00.440" = 24.0167889245° ================================================================= Applied Auxiliary Computations Time Factors Corresponding to Full Astronomical JD T = 0.255024903985 Julian centuries reckoned from J2000.0 t = 0.025502490398 Julian millennia reckoned from J2000.0 Nutations (IAU 2000B Series) +2.821" = +0.0007836768° = Nutation in ecliptical longitude +8.599" = +0.0023887227° = Nutation in ecliptical obliquity +0.173s = +0.0007190145° = Equation of the equinoxes Mean Obliquity of the Ecliptic 23° 26' 09.510" = 23.4359751350° True Obliquity of the Ecliptic 23° 26' 18.110" = 23.4383638576°
Jay Tanner - PHP Science Labs - 2025 - 1.7