Local Sidereal Time Clock

by Matt Oltersdorf 2003 10 26 18:10 UTC
back to Java for Astronomy


 

 

 Date:             Local Time:         

Location:

Longitude

deg

  Time Zone:

 

Local Date and Time:

UT is:

the Julian Day is:

the Local Sidereal Time is:

the Declination of the Sun is:

deg

the Equation of Time is:

min

The Julian Day (JD), used in astronomical algorithms, is the number of days since noon at Greenwich, England on 1 Jan 4713 BC.

The sidereal time is measured by the rotation of the Earth, with respect to the stars (rather than relative to the Sun). Local sidereal time is the right ascension (RA, an equatorial coordinate) of a star on the observers meridian. One sidereal day corresponds to the time taken for the Earth to rotate once with respect to the stars and lasts approximately 23 h 56 min.

The sidereal time is a direct indication of whether a celestial object of known right ascension is observable at that instant.  

Last Update: