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
2460834.5
0.008750000000
-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 08 [Sunday] Gregorian JD Number = 2460835 JD00 = 2460834.5 = JD for 00h of date Local Time = 00:12:36 = 0.008750000000 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) = 2460834.717083333333 Longitude = -76° 49' 23.915" = -76.8233097222° (W) = -05h 07m 17.594s = -5.1215539815 h ================================================================= Local Mean Sidereal Time at Longitude -76.8233097222° (W) 17h 12m 41.403s = 17.2115007055 h 258° 10' 21.04" = 258.1725105820° Local True Sidereal Time at Longitude = -76.8233097222° (W) 17h 12m 41.482s = 17.2115229143 h 258° 10' 22.24" = 258.1728437149° Greenwich Mean Sidereal Time 22h 19m 58.997s = 22.3330546870 h 334° 59' 44.953" = 334.9958203044° Greenwich True Sidereal Time 22h 19m 59.077s = 22.3330768958 h 334° 59' 46.152" = 334.9961534372° ================================================================= Applied Auxiliary Computations Time Factors Corresponding to Full Astronomical JD T = 0.254338592288 Julian centuries reckoned from J2000.0 t = 0.025433859228 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) +1.307" = +0.0003630921° = Nutation in ecliptical longitude +8.546" = +0.0023738852° = Nutation in ecliptical obliquity +0.080s = +0.0003331329° = Equation of the equinoxes Mean Ecliptic Obliquity 23° 26' 09.543" = 23.4359840587° Nutation in Obliquity +8.546" = +0.0023738852° True Ecliptic Obliquity 23° 26' 18.089" = 23.4383579439°
Jay Tanner - PHP Science Labs - 2025 - 1.7