This clock with automatically show you the sidereal time, and it will save you having to calculating it based on the normal or universal time. Sidereal Clock only requires that you provide it with the length and latitude values to be able to calculate the exact sidereal time. To make this location easier, you will be able to use an Earth globe, and by means of the right button mark the coordinates of the location that you want the sidereal time for. It also allows you to automatically detect the time zone that you are in.
If you're interested in astronomy, with Sidereal Clock you'll be aware of the sidereal time anywhere in the world.