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
2461103.5
0.124907407407
-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 Mar 04 [Wednesday] Gregorian JD Number = 2461104 JD00 = 2461103.5 = JD for 00h of date Local Time = 02:59:52 = 0.124907407407 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) = 2461103.83324074074 Longitude = -76° 49' 23.915" = -76.8233097222° (W) = -05h 07m 17.594s = -5.1215539815 h ================================================================= Local Mean Sidereal Time at Longitude -76.8233097222° (W) 13h 40m 58.275s = 13.6828540332 h 205° 14' 34.12" = 205.2428104985° Local True Sidereal Time at Longitude = -76.8233097222° (W) 13h 40m 58.705s = 13.6829735323 h 205° 14' 40.57" = 205.2446029850° Greenwich Mean Sidereal Time 18h 48m 15.869s = 18.8044080147 h 282° 03' 58.033" = 282.0661202208° Greenwich True Sidereal Time 18h 48m 16.299s = 18.8045275138 h 282° 04' 04.486" = 282.0679127074° ================================================================= Applied Auxiliary Computations Time Factors Corresponding to Full Astronomical JD T = 0.261706591122 Julian centuries reckoned from J2000.0 t = 0.026170659112 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) +7.033" = +0.0019536892° = Nutation in ecliptical longitude +9.121" = +0.0025337054° = Nutation in ecliptical obliquity +0.430s = +0.0017924866° = Equation of the equinoxes Mean Ecliptic Obliquity 23° 26' 09.198" = 23.4358882564° Nutation in Obliquity +9.121" = +0.0025337054° True Ecliptic Obliquity 23° 26' 18.319" = 23.4384219618°
Jay Tanner - PHP Science Labs - 2026 - 1.7