Local Sidereal Time Clock

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.  

Page Retrieved:

Sunday, February 05, 2012 08:57 UTC

Send a link to this page by email.