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
2460798.5
0.168715277778
-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 May 03 [Saturday] Gregorian JD Number = 2460799 JD00 = 2460798.5 = JD for 00h of date Local Time = 04:02:57 = 0.168715277778 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) = 2460798.877048611111 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 41m 44.250s = 18.6956249674 h 280° 26' 03.75" = 280.4343745108° Local True Sidereal Time at Longitude = -76.8233097222° (W) 18h 41m 44.288s = 18.6956356061 h 280° 26' 04.32" = 280.4345340921° Greenwich Mean Sidereal Time 23h 49m 01.844s = 23.8171789489 h 357° 15' 27.663" = 357.2576842331° Greenwich True Sidereal Time 23h 49m 01.883s = 23.8171895876 h 357° 15' 28.238" = 357.2578438145° ================================================================= Applied Auxiliary Computations Time Factors Corresponding to Full Astronomical JD T = 0.253357345615 Julian centuries reckoned from J2000.0 t = 0.025335734561 Julian millennia reckoned from J2000.0 Nutations (IAU 2000B Series) +0.626" = +0.0001739330° = Nutation in ecliptical longitude +9.050" = +0.0025139265° = Nutation in ecliptical obliquity +0.038s = +0.0001595813° = Equation of the equinoxes Mean Obliquity of the Ecliptic 23° 26' 09.589" = 23.4359968174° True Obliquity of the Ecliptic 23° 26' 18.639" = 23.4385107439°
Jay Tanner - PHP Science Labs - 2025 - 1.7