Sidereal Tompion Regulator New description coming soon ... This very complex clock is thought to be the first sidereal regulator also to show mean solar time through a geared mechanism. Since the clock was first re-discovered in the 1970s there has been much speculation as to whether it was originally set up primarily as a sidereal regulator or as a mean solar time regulator. As a mean time regulator it is possible to calculate sidereal time by subtracting the difference between the dials from that shown on the inner dial. However with an almanac and a simple addition, it is easy to calculate sidereal time from mean solar time so this calculation of sidereal time appears irrational.
