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
2460853.5
0.048414351852
-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 Jun 27 [Friday] Gregorian JD Number = 2460854 JD00 = 2460853.5 = JD for 00h of date Local Time = 01:09:43 = 0.048414351852 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) = 2460853.756747685185 Longitude = -76° 49' 23.915" = -76.8233097222° (W) = -05h 07m 17.594s = -5.1215539815 h ================================================================= Local Mean Sidereal Time at Longitude -76.8233097222° (W) 19h 24m 52.337s = 19.4145381582 h 291° 13' 05.06" = 291.2180723734° Local True Sidereal Time at Longitude = -76.8233097222° (W) 19h 24m 52.515s = 19.4145874805 h 291° 13' 07.72" = 291.2188122071° Greenwich Mean Sidereal Time 00h 32m 09.932s = 0.5360921397 h 08° 02' 28.976" = 8.0413820958° Greenwich True Sidereal Time 00h 32m 10.109s = 0.5361414620 h 08° 02' 31.639" = 8.0421219294° ================================================================= Applied Auxiliary Computations Time Factors Corresponding to Full Astronomical JD T = 0.254859869888 Julian centuries reckoned from J2000.0 t = 0.025485986988 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) +2.903" = +0.0008063680° = Nutation in ecliptical longitude +8.417" = +0.0023381627° = Nutation in ecliptical obliquity +0.178s = +0.0007398337° = Equation of the equinoxes Mean Ecliptic Obliquity 23° 26' 09.518" = 23.4359772808° Nutation in Obliquity +8.417" = +0.0023381627° True Ecliptic Obliquity 23° 26' 17.936" = 23.4383154436°
Jay Tanner - PHP Science Labs - 2025 - 1.7