The nice thing a timescales is that there are so many to choose from: solar, atomic, sidereal, local, apparent, dynamical. Here is a javascript clock showing some of the more well-known. The latitude and longitude are modifiable and affect the values of the local times and UT0. Earth rotation parameters use the estimation formulas from a recent IERS Bulletin A.

The clock has several manifestations, controlled by the style sheet used:

This was written partly as an exercise in javascript and CSS and I would be happy to hear of any problems or bugs.

Values are generally displayed to a ludicrous precision, the accuracy may be rather less. In particular, values for Sun Right Ascension and Declination may be 10-20 arcsecs out.


For another clock see: An Astronomical Clock

Other web pages I found useful:

An excellent introduction to timescales.

IERS Bulletin A. The very latest data on the rotation of the earth and the relation between UT0, UT1 and UT2.

The relation between apparent and mean sidereal time.

More on sidereal time and the equation of the equinoxes.