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
2460738.5
0.165659722222
-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 Mar 04 [Tuesday] Gregorian JD Number = 2460739 JD00 = 2460738.5 = JD for 00h of date Local Time = 03:58:33 = 0.165659722222 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) = 2460738.873993055555 Longitude = -76° 49' 23.915" = -76.8233097222° (W) = -05h 07m 17.594s = -5.1215539815 h ================================================================= Local Mean Sidereal Time at Longitude -76.8233097222° (W) 14h 40m 46.205s = 14.6795013628 h 220° 11' 33.07" = 220.1925204419° Local True Sidereal Time at Longitude = -76.8233097222° (W) 14h 40m 46.274s = 14.6795204818 h 220° 11' 34.11" = 220.1928072272° Greenwich Mean Sidereal Time 19h 48m 03.799s = 19.8010553443 h 297° 00' 56.989" = 297.0158301643° Greenwich True Sidereal Time 19h 48m 03.868s = 19.8010744633 h 297° 00' 58.021" = 297.0161169496° ================================================================= Applied Auxiliary Computations Time Factors Corresponding to Full Astronomical JD T = 0.251714551486 Julian centuries reckoned from J2000.0 t = 0.025171455148 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) +1.125" = +0.0003125772° = Nutation in ecliptical longitude +9.606" = +0.0026683760° = Nutation in ecliptical obliquity +0.069s = +0.0002867853° = Equation of the equinoxes Mean Ecliptic Obliquity 23° 26' 09.665" = 23.4360181778° Nutation in Obliquity +9.606" = +0.0026683760° True Ecliptic Obliquity 23° 26' 19.272" = 23.4386865538°
Jay Tanner - PHP Science Labs - 2025 - 1.7