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
2461239.5
0.150335648148
-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 Jul 18 [Saturday] Gregorian JD Number = 2461240 JD00 = 2461239.5 = JD for 00h of date Local Time = 03:36:29 = 0.150335648148 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) = 2461239.858668981481 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 13m 52.820s = 23.2313388659 h 348° 28' 12.30" = 348.4700829890° Local True Sidereal Time at Longitude = -76.8233097222° (W) 23h 13m 53.380s = 23.2314944587 h 348° 28' 20.70" = 348.4724168801° Greenwich Mean Sidereal Time 04h 21m 10.414s = 4.3528928474 h 65° 17' 36.214" = 65.2933927113° Greenwich True Sidereal Time 04h 21m 10.974s = 4.3530484402 h 65° 17' 44.616" = 65.2957266025° ================================================================= Applied Auxiliary Computations Time Factors Corresponding to Full Astronomical JD T = 0.265430764380 Julian centuries reckoned from J2000.0 t = 0.026543076438 Julian millennia reckoned from J2000.0 Nutations (IAU 2000B Series) +9.158" = +0.0025437757° = Nutation in ecliptical longitude +7.810" = +0.0021693072° = Nutation in ecliptical obliquity +0.560s = +0.0023338912° = Equation of the equinoxes Mean Obliquity of the Ecliptic 23° 26' 09.023" = 23.4358398328° True Obliquity of the Ecliptic 23° 26' 16.833" = 23.4380091400°
Jay Tanner - PHP Science Labs - 2026 - 1.7